Catad_tema Functional and laboratory diagnostic methods - articles

Catad_tema Peptic ulcer - articles

Indications and methods for testing patients for Helicobacter pylori

ORIGINAL RESEARCH P.Ya. Grigoriev, V.G. Zhukhovitsky*, E.P. Yakovenko, E.V. Talanova
Federal Gastroenterological Center at the Republican Clinical Hospital No. 2 of the Ministry of Health of the Russian Federation,
* State Clinical Hospital named after. S.P. Botkin. Moscow

Currently, the role of Helicobacter pylori (Hp) in the pathogenesis of gastritis, duodenitis, gastric and duodenal ulcers, gastric lymphoma and even gastric cancer has been proven.

Diagnosis of HP infection can be carried out using methods that directly detect the bacterium in a biopsy sample of the patient’s gastroduodenal mucosa, or the presence of HP is judged by the presence of its waste products. The following tests are currently used: bacteriological, histological (or cytological), urease, polymerase chain reaction.

For primary diagnosis, urease and histological methods with taking a biopsy through an endoscope are more often used. Diagnostic tests to determine Hp are particularly useful in determining the adequacy of eradication drug therapy.

INDICATION HP EXAMINATION IN THE PATIENTS AND THE METHODS OF HP EXPOSE

P.la. Grigoryev, V.G. Gzuxovitskyi, E.P. Iakovenko, E.V. Talanova

The HP role in the pathogenesis of gastritis, duodenitis, peptic ulcer, gastric lymphoma and gastric tumor is proven at the present time. HP infection is revealed with bacteria in gastroduodenal mucosa or with method, which is revealed the products of its vital activity. There are next special methods for HP expose: bacteriological, histological, urease method, polymerasse chain reaction. Urease and histological methods are usually used for primary diagnosis. The methods of HP expose are especially important for HP eradication control.

15 years have passed since a spiral-shaped bacterium was discovered, isolated from a biopsy of the gastric mucosa of a patient with antral gastritis (B. Marshall, D. Warren, Australia). It has been established that this microorganism, called Helicobacter pylori (HP), is a gram-negative, actively motile, oxidase- and catalase-positive, microaerophilic bacterium with an unusually high level of urease production, which plays a significant role in the metabolism of HP and is decisive in the colonization of CO, protected from banal microflora with hydrochloric acid - one of the most powerful nonspecific factors of natural resistance. Numerous studies conducted over the past years by scientists from different countries have revealed the pathogenesis of many gastroduodenal diseases and shown that the destruction (eradication) of the pathogen using drug combinations leads to the disappearance of symptoms of diseases associated with HP. After successful eradication therapy, not only microorganisms that persist in the gastric mucosa and duodenum disappear, but also signs of specific inflammation (infiltration of interepithelial spaces and lamina propria with polymorphonuclear neutrophils, lymphocytes and plasma cells), and in some cases metaplasia, dysplasia and even atrophy regress. The progressive course of gastroduodenitis with recurrence of ulcers in the stomach or duodenum is more often associated with the ineffectiveness of eradication therapy and less often with reinfection, that is, with re-infection of HP. The role of HP in the pathogenesis of gastritis, duodenitis, gastric ulcer (GUD), duodenal ulcer (DU), MALT lymphoma of the stomach (mucosal associated lymphoid tissue) and even gastric cancer (scheme) has been proven.

Scheme
Clinical variants of HP infection

Since HP plays such a prominent role in the pathogenesis of very serious diseases of the gastroduodenal region, microbiological diagnosis of Helicobacter pylori lesions should rightfully be given a place in the complex of diagnostic measures. This kind of diagnosis can be carried out using various research methods that allow direct or indirect verification of the presence of HP in the mucus of the stomach and (or) duodenum. Microbiological methods for direct detection of HP include a microscopic method of research, performed simultaneously with histological (occasionally - cytological), and a bacteriological method of research - both in the classical arrangement, which involves isolating a pure culture of HP and identifying it, and in an arrangement based on the use of polymerase chain reaction (PCR), which makes it possible to identify HP without isolating a pure culture: by the fragments of its genome present in the material under study. Microbiological methods for indirect detection of HP include the serological research method and the bacteriological research method in non-traditional, very unexpected, at first glance, arrangements: rapid urease and breath tests. None of the listed research methods, no matter how they are performed, is absolutely reliable or at least the most preferable: the choice of research method(s) is determined by the clinical features of the diagnostic case, the level of equipment of the microbiological laboratory and the medical institution as a whole, the cost of the study, the patient’s consent to perform a particular test.

With the exception of respiratory tests, all of the listed tests, no matter what research method they are performed, are invasive: the test material for microscopic and bacteriological research methods is a biopsy specimen of CO or other localization obtained during upper esophagogastroduodenoscopy using targeted biopsy; blood serum serves as material for serological research; The non-invasive breath test examines the air you exhale. Obviously, the collection of samples of CO remains within the competence of the endoscopist, while samples of blood and exhaled air can be collected by the efforts of nursing staff. An endoscopist in the endoscopy room also performs a quick urease test; a gastroenterologist can perform tests for the accelerated detection of antibodies to HP - a very common arrangement of the serological research method at present, which does not require special equipment; all other types of laboratory research can be fully carried out only in specialized laboratories of the appropriate profile - pathomorphological, bacteriological, isotope diagnostics - often located outside not only the medical institution, but also outside the cities and countries (!) where it is the institution is located.

According to the requirements of the Sydney Classification of Gastritis (Sydney, 1990; Houston, 1994), the reliability of the results of histological and microscopic diagnosis is ensured by the study of four samples of CO, selected in a strictly defined manner in the antrum and body of the stomach; performing a rapid urease test requires the availability of a separate sample of CO; To perform a bacteriological study, two such samples are required. For histological and microscopic diagnosis of peptic ulcer disease, regardless of the location of the ulcer, samples of mucus from the antrum and body of the stomach, as well as the preulcerous zone are examined: the zone of gastritis or duodenitis surrounding the gastric or duodenal ulcer; two separate samples are subject to bacteriological examination, one is subject to examination using a rapid urease test; selection of material from an ulcer crater can be regarded as obviously useless: HP is spontaneously eliminated from areas of necrotic CO, deprived of the adhesion receptors necessary for its fixation - an attribute of the apical surfaces of cells of the surface epithelium of the stomach or cells of the epithelium of the duodenal bulb that have undergone metaplasia of the gastric type. The selection of central or peripheral blood samples necessary for serological diagnosis and obtaining serum from them are carried out in the usual way. Exhaled air samples required to perform a breath test are collected in special, reliably sealed laboratory containers.

Samples of CO, subject to immediate histological and microscopic examination, are placed in fixing solutions and transported to the pathomorphology laboratory; CO samples subject to bacteriological examination are immediately after collection placed in a transport medium and transported to the bacteriological laboratory, and as soon as possible; samples of blood or serum are sent to the bacteriological laboratory no later than two days from the moment of collection; exhaled air samples are transported to the isotope diagnostic laboratory without any time restrictions.

During a microscopic examination, performed, as noted above, simultaneously with a histological one, in smears stained in one way or another, the nature of inflammation, the activity of gastritis, the presence and severity of atrophy and (or) intestinal metaplasia are assessed, and, secondly, , the presence of HP and the degree of CO contamination with it.

The bacteriological research method is the most important method for microbiological diagnosis of helicobacteriosis, during which a viable culture is isolated from a homogenized sample of CO, sown on an artificial nutrient medium of one or another - and very complex - composition and cultivated in a microaerophilic - oxygen-depleted and carbon dioxide-enriched atmosphere HP, available for comprehensive assessment: typing, epidemiological marking, assessment of sensitivity to antibiotics, identification of pathogenicity factors, experimental study. Isolated HP cultures are subject to museum storage under deep-freezing conditions, which makes it possible to compare cultures isolated at different times from the same patient, thereby differentiating cases of relapse, reinfection, and superinfection.

PCR technology has opened up new possibilities for the bacteriological diagnosis of helicobacteriosis: identification of HP not only in pure cultures, but also directly in the material under study, bypassing the labor-intensive, time-consuming and expensive procedure of cultivating it on artificial nutrient media. In both cases, the identification of HP is based on the identification of a fragment of a particular HP gene, which is detected by primers complementary to its flanks - synthetic oligonucleotides of a known composition (primers) - and is copied (amplified) many times in the presence of the original enzyme in a strictly specified mode, maintained by one intended for this purpose. a programmable device - a thermal cycler (amplifier).

Both rapid urease and breath tests are based on the principle of detecting urease activity in a sample of CO and in exhaled air, respectively; although in both cases, which do not involve the isolation of a pure culture of HP, the source of this type of activity remains fundamentally unrefined, the specificity of both tests is given precisely by the high level of urease production characteristic of HP: other urease producers - Proteus, Staphylococcus, Candida - often, mainly, with anacid gastritis, present in the stomach, have a significantly lower level of urease production and manifest their urease activity at a significantly later time than HP. As part of the rapid urease test, the presence of urease activity is determined by a change in the color of the indicator that reacts to the alkalization of the urea-containing base, which occurs due to the hydrolysis of urea to ammonia in the presence of urease; Obviously, the correct interpretation of the results of the test in question is largely determined by compliance with the requirement to take into account the results within the time limits established by the methodological recommendations. The second product of urea hydrolysis in the presence of urease - carbon dioxide - can be detected in gaseous form in exhaled air as part of a breath test - provided that its molecules include an indicator isotope of carbon - 13 C or 14 C - originally included as a label in the composition of urea molecules taken orally by the patient a few minutes before taking the test sample: the presence of the indicator isotope is recorded scintillographically or mass spectrometrically in significantly higher quantities and at a significantly earlier time in the exhaled air of patients whose mucous membranes are colonized with HP than in persons free from HP .

The serological research method occupies a very important place in the microbiological diagnosis of helicobacteriosis and the most important one in population-epidemiological studies: with its help, the patient’s humoral immune response to HP antigens is assessed. The most specific and sensitive, as well as the most labor-intensive and expensive, are tests based on the use of immunoblotting: with their help, antibodies of classes M, G, A can be detected to various HP antigens, including those of its antigens, antibodies to which are not identified using other, more accessible and easy-to-use techniques.

The most common test for the serological diagnosis of helicobacteriosis remains the indirect enzyme-linked immunosorbent assay (ELISA), which makes it possible to detect antibodies of classes M, G, A to many, although not all, HP antigens that are significant for diagnosis with relatively high specificity and sensitivity at a relatively low cost. Finally, the so-called “rapid tests”, which have become widespread in recent years, based on the principle of “dry” chromatographic separation of serum proteins with subsequent binding of immunoglobulins with their corresponding antigens immobilized on a carrier, remain indispensable in screening patients, determining the strategy and tactics of subsequent observations: with the help of tests of this kind, the polyvalent humoral immune response to the HP antigen complex can be qualitatively assessed; the relatively low level of specificity and sensitivity of these tests requires special correctness in interpreting the results they produce - only strict compliance with the last condition gives the right to the widespread use of such tests, the attractiveness of which is largely due to their low cost and the insignificance of labor costs required for their implementation.

Many recommendations emphasize that due to the high cost of tests, the result of eradication therapy should not be confirmed in all cases, but these studies are mandatory for gastric lymphoma complicated by gastric ulcer and peptic ulcer (ulcer bleeding, etc.), as well as after resection of early gastric cancer . In other situations, these issues are resolved individually, however, the result of eradication therapy can be reliably assessed if tests for HP are carried out no earlier than 4 weeks after the cessation of all types of drug treatment. For gastric ulcers and gastric lymphoma in remission due to combination drug therapy, control endoscopy, multiple targeted biopsies, brush cytology and histology of biopsy specimens are mandatory.

Cultures for HP and determination of its sensitivity to antibacterial drugs are carried out in the absence of the effect of eradication therapy after a course of combination therapy and in the recurrent course of the disease.

Many tests used to diagnose HP are informative, but their results depend on the correctness of the collection of material for research, the accuracy of the technique and a number of other circumstances, and therefore sometimes false positive and false negative conclusions arise when examining biopsy specimens.

Diagnostic tests for HP are particularly useful in determining the adequacy of drug eradication therapy. When choosing a method for diagnosing HP, the clinical manifestations of pyloric helicobacteriosis should be taken into account. In this regard, it becomes appropriate to consider some of the most typical clinical situations.

1. A patient with a diagnosed peptic ulcer associated with HP received a course of eradication drug therapy (10 days) and prolonged treatment with an antisecretory drug for 8 weeks. The symptoms that the patient had before starting treatment were relieved by therapy within a week. Esophagogastroduodenoscopy, biopsy, histology and tests for HP after 4 weeks or more may not be performed, but if the patient insists, then only a urease breath test is advisable. Some experts believe that when a duodenal ulcer is detected, there is no need to conduct tests for Hp at all, since in these patients in 95% of cases, gastroduodenal ulcer infection is detected. However, in this situation, the fact of the presence of Hp infection is not as important as its absence. Negative tests for HP prompt the doctor to find out other causes of duodenal ulcers (Zollinger-Ellison syndrome, Crohn's disease, NSAID use).

2. Patients with gastroesophageal reflux disease due to recurrent reflux esophagitis often take omeprazole or analogues for a long time, and yet it is known that even in the presence of antral Helicobacter gastritis, translocation of Hp occurs from the antrum to the body of the stomach, in connection with this pangastritis develops, and subsequently, atrophy progresses, often preceding stomach cancer. In this situation, testing for Hp and eradication therapy are justified, but in this case, eradication therapy is better carried out before prescribing proton pump blockers, that is, studies on Hp are almost always justified by the advisability of a subsequent course of eradication therapy.

3. Ulcer-like dyspeptic disorders that appeared for the first time. They can be a manifestation of many diseases of the upper digestive tract, but to clarify the disease it is necessary: ​​esophagogastroduodenoscopy, targeted biopsy and a quick urease test for HP. If an ulcer is detected in the stomach, it is necessary to conduct brush cytology and histological examination of biopsy specimens; if an ulcer is detected in the duodenum, one can limit oneself to brush cytology and a rapid urease test; in the absence of ulcerations in the mucus, a histological examination is necessary to determine the activity, severity and prevalence of gastritis associated with HP or with other pathological factors. In this clinical situation, a urease test is justified, since for all of the listed diseases associated with HP, combined eradication drug therapy is indicated.

4. Hungry night pain in the epigastric region reappeared in a patient who a year ago was treated for an exacerbation of a peptic ulcer with localization of a recurrent ulcer in the duodenum, which developed against the background of chronic active gastroduodenitis associated with HP. Before prescribing combination drug therapy taking into account HP, it is advisable to conduct a urease breath test with 13 C or 14 C, or a test to determine antibodies to HP.

5. While taking acetylsalicylic acid, a patient with dyspeptic syndrome had one vomiting of “coffee grounds” type contents and two loose black stools. Urgent esophagogastroduodenoscopy, targeted biopsy, cytology with Giemsa staining and a urease test are necessary, since in patients taking NSAIDs, gastroduodenal ulceration and bleeding are more often associated with the presence of chronic active gastroduodenitis, associated not only with NSAIDs, but also with HP. These patients should undergo eradication therapy.

Many studies conducted in recent years have focused on the role of infection Helicobacter pylori(HP) in the development of chronic gastroduodenal pathology in children. Currently, a large number of methods for diagnosing HP infection have been developed, and various treatment programs for HP-associated diseases have been proposed. However, as we delve deeper into this problem and obtain new data, contradictions accumulate, and many provisions that seemed unshakable just a few years ago do not look so clear today. In this article, we tried to draw attention to some controversial issues and ambiguous provisions in the study of HP-associated pathology in children.

HP infection is considered one of the most common in the world. It affects about half of the world's population, but chronic gastroduodenitis and peptic ulcers develop only in a portion of those infected. Since the discovery of HP in 1983 by Warren et Marshall, it has been generally accepted that HP is the main etiological factor in the development of chronic gastroduodenitis, gastric and duodenal ulcers, gastric adenocarcinoma and B-cell MALT lymphoma.

According to the literature, in chronic gastritis, HP infection is detected in 60-80% of cases, and in peptic ulcer disease - in 98-100% of cases. However, according to our data, when examining 240 children aged 7-16 years with chronic gastroduodenal pathology, carried out using a set of diagnostic methods, the presence of HP infection was confirmed in 140 children (58.5% of cases). The frequency of HP infection depended on the morphological form of gastroduodenitis and was maximum in erosive and ulcerative lesions of the coolant (80%), while in duodenal ulcer it was only 85%. Consequently, there is a significant proportion of patients with HP-negative gastroduodenal pathology, the cause of which has yet to be clarified, since all the factors known so far that lead to the development of gastroduodenal diseases (nutritional disorders, stressors, hereditary predisposition, previous diseases, etc.) were observed with equal frequency in the groups of HP(+) and HP(-) patients.

In modern gastroenterology, the dominant role of HP in the pathogenesis of gastroduodenal pathology is recognized, and this pathogen is usually considered a pathogen. As a result, many gastroduodenal diseases, previously known as multifactorial, are now sometimes considered to be predominantly infectious. However, a microorganism can be classified as pathogenic if it fully complies with Koch’s three classical postulates. The first postulate states that the pathogenic microorganism obtained from a patient must be cultivated in its pure form. This provision is completely true for HP. According to Koch's second postulate, a microorganism should always be detected in a given disease, and HP is not detected in 100% of cases of gastroduodenal diseases. Finally, Koch's third postulate assumes that the introduction of a pure culture of a pathogen always causes the development of identical pathological changes in another organism. However, according to the literature, when a pure HP culture is administered to volunteers, only one out of 8-10 people develops gastritis, and an experimental model of HP-associated peptic ulcer disease still does not exist. Thus, only one of Koch’s three classical postulates is fully valid for NR.

According to many microbiologists and infectious disease specialists, HP is an opportunistic microorganism. If we consider conditional pathogenicity as the ability of a microorganism to cause a pathological process only under certain conditions, then the result of the interaction between the macroorganism and the pathogen largely depends not only on the virulent properties of the pathogen, but also on the immunological reactivity of the macroorganism.

Clinical and epidemiological studies in recent years also show that the pathogenetic significance of HP is ambiguous. The presence of HP in the stomach is associated with an increased risk of developing peptic ulcers and adenocarcinoma, and the absence of HP is associated with a high risk of developing gastroesophageal reflux disease and its sequelae, Barrett's esophagus and esophageal adenocarcinoma. Thus, virulence and protection are not absolute. Discussions on this topic are still ongoing and are of fundamental importance, because the answer to the main question will depend on their outcome: should we always strive to eradicate the microbe?

In pediatric practice, the clinical manifestations of HP infection are very diverse - asymptomatic carriage, chronic gastroduodenitis (including erosive gastroduodenitis), gastric and duodenal ulcers. In patients with histologically unchanged mucosa of the gastroduodenal zone, HP is detected only in 8-10% of cases. What determines the formation of one or another form of HP infection? Apparently, HP can manifest its pathological properties only when the balance in the microecological system of the stomach is disturbed and the local immunological defense of the gastroduodenal mucosa changes. If the host's protective factors (mucosal barrier, mucin, complement, epithelial lining, peristalsis, acid production) are inadequate, then HP realizes its pathogenic properties and an inflammatory response to the microbe develops. According to Blazer M.J., HP realizes its pathogenicity by regulating the expression of various genes to the extent that this is dictated by the reaction of the macroorganism.

What microorganism factors contribute to the colonization and persistence of the microbe in the coolant? As is known, Helicobacter pylori are small, gram-negative, motile, spiral-shaped bacteria that are well adapted to the conditions of colonization in the coolant. The microbe has a wide range of pathogenicity factors, produces vacuolating cytotoxin (VacA), cytotoxin-associated protein (CagA), numerous enzymes - urease, catalase, oxidase, alkaline phosphatase, γ-glutamyl transpeptidase, phospholipase, etc. Bacterial factors contributing to the colonization of HP in the gastric mucosa are urease, adhesins, flagella, and g-glutamyl transpeptidase. HP factors that contribute to persistence and inflammatory response are cell wall LPS, urease, VacA, CagA island genes.

There are a number of scientific works devoted to genome research H. pylori. The genome of this microorganism is relatively small and almost completely deciphered. However, many authors pay attention to interesting features of the molecular genetic organization of this pathogen. More than 40 HP pathogenicity genes are collected in one chromosome segment, called the “pathogenicity island.” But constant recombination between different HP strains leads to genome instability. It is the instability and variability of the HP genome that some authors explain the variety of clinical manifestations of the infection. Probably, this quality of the microbe helps it “escape” the host’s immune system, as a result of which the immunological response to HP is insufficient. Finally, the variability of the microorganism's genome allows it to quickly acquire resistance to antibacterial drugs, which creates additional difficulties in finding adequate therapy for HP-associated diseases. It has even been suggested that if H. pylori we are dealing not with one type of microbe, but with a complex of its “cryptic” species. Of course, in order to understand the mechanism of development of the infectious process and solve the problems of therapy and specific prevention of HP infection, it is necessary to further study pathogenicity factors H. pylori .

Currently, many works have appeared in the press devoted to the study of the role of HP pathogenicity factors in the development of erosive and ulcerative lesions of the coolant. Many researchers show that CagA-positive strains are more often associated with erosive and ulcerative changes in the gastric mucosa, causing more significant neutrophilic-lymphocytic infiltration of the gastric mucosa and epithelial degeneration. It has been proven that CagA-positive strains are 5 times more dense than CagA-negative strains in the colonization density of the coolant. Many authors call CagA(+) strains of HP ulcerogenic and carcinogenic and consider the detection of specific antibodies to CagA toxin in the blood of patients as a serological marker for anti-Helicobacter therapy. However, there are researchers who do not note the relationship between the severity of changes in the coolant and the toxicogenicity of the pathogen strain.

According to our data, out of 140 HP-infected children, 103 children (74%) were found to have a high titer of specific antibodies to CagA based on blood ELISA results. The frequency of toxigenic CagA(+) strains of HP in superficial gastroduodenitis was 53.3%, in erosive gastroduodenitis - 82.2%, in duodenal ulcer - 79.3%. It is in this group of children that nodular gastroduodenitis, erosive gastroduodenitis and duodenal ulcer are significantly more common (p<0,05).

Urease HP is considered one of the important factors in the pathogenicity of the microbe and provides it with comfortable living conditions in the acidic environment of the stomach. There is evidence that urease can activate neutrophils and monocytes even without invasion into the epithelial layer. However, in our study, the titer of antibodies to recombinant HP urease was low in HP(+) and HP(-) children and did not depend on the form of lesion of the gastric mucosa. Data from foreign authors also confirm the presence of a low immune response to urease, and therefore the conclusion was made about the weak immunogenicity of urease.

The pathogenesis of HP infection can be presented in three aspects.

• The first stage is the entry and adhesion of the microbe. The bacterium moves well in viscous mucus with the help of powerful flagella. Urease, located not only in the cytoplasm of HP, but also on the surface of cells, breaks down the urea of ​​gastric juice into ammonia and protects the microbe from the action of hydrochloric acid. The bacterium adheres to the surface of gastric epithelial cells, where phospholipase destroys the outer phospholipid layer of the membrane, as a result of which the microbe penetrates into the epithelial cells. However, invasion and adhesion alone are not enough for the development of a pathological process. The vacuolating cytotoxin HP is capable of causing the formation of large vacuoles, which leads to cell degeneration. Cell destruction is the first stage in the formation of acute erosion, and then ulcers.
• The second stage of pathogenesis is interaction or “evasion” from the host’s immune system. The adhesion of the microbe, its release of cytotoxins and enzymes, and colonization of the coolant lead to the launch of humoral and cellular responses of the macroorganism. HP components stimulate the production of proinflammatory cytokines, which leads to the migration of inflammatory cells and their release of reactive oxygen metabolites and myeloperoxidase. HP infection leads to the development of chronic inflammation in the gastric mucosa, which is histologically characterized by epithelial degeneration and infiltration of inflammatory cells. The migration and activation of immunocompetent cells in the gastric mucosa is induced both by bacterial factors of the microbe itself and by the released proinflammatory cytokines IL-1β, IL-8, IL-6, TNF-α, and macrophage chemotaxis factor.

We studied the production of proinflammatory cytokines IL-1α, IL-1β and IL-8 by GM cells in HP(+) and HP(-) children. In an immunohistochemical study of cryosections of gastric biopsies using indirect immunohistochemistry, the production of IL-1α was recorded only in HP(+) children and was not detected in HP(-) patients. The levels of IL-1β and IL-8 production in the coolant were significantly increased in HP(+) children (p<0,05). Так, продукция ИЛ-1β клетками СОЖ была подтверждена у 73,7% НР(+) детей и только у 38,5% НР(-) детей. Кроме того, максимально высокая продукция ИЛ-1β отмечалась в группе детей с НР-ассоциированными эрозивно-язвенными повреждениями СОЖ. Продукция ИЛ-8 клетками СОЖ была зафиксирована у 70% НР(+) детей и лишь у 30% НР(-) детей (рис. 1). Таким образом, доказано, что НР вызывает значительную стимуляцию продукции провоспалительных цитокинов в СОЖ, что позволяет поддерживать местный воспалительный ответ, но не влияет на выраженность микробной колонизации.

With HP gastritis, neutrophilic and lymphocytic infiltration of the coolant (with a predominance of type 1 Tx) is histologically revealed, and neutrophilic infiltration of the coolant is considered the main sign of gastritis activity. During the study, the production of endogenous hydrogen peroxide and myeloperoxidase by cells of the gastric mucosa was studied as an indirect marker of leukocyte (neutrophil) infiltration of the gastric mucosa. An immunohistochemical study revealed high activity of production of hydrogen peroxide and myeloperoxidase by cells of the gastric mucosa in both HP(+) and HP(-) children (Fig. 2). Thus, these indicators indicate the activity of mucosal inflammation regardless of HP infection and can be considered as nonspecific markers of the inflammatory response.

The infiltration of the gastric mucosa by B-lymphocytes, which are grouped in the lamina propria of the gastric mucosa, around the foci of HP proliferation and foci of intestinal metaplasia, also increases. Immature B-lymphocytes form reproduction centers (foci of lymphofollicular hyperplasia of the mucosa), described during FGDS as nodular elements. However, the migration of immunocompetent cells to the site of inflammation does not affect the degree of contamination of the mucosa. The mechanisms of the tissue immune response are still not completely clear.

The “cytokine network” promotes the activation of not only the T-cell component, but also the B-lymphocytes responsible for the synthesis of anti-Helicobacter antibodies. Determination of specific Ig G for HP is the basis of the serological method for the primary diagnosis of HP infection. In older children, a humoral response is formed 18-60 days after infection and the antibody titer persists for a long time even after successful eradication, which does not allow the use of serological tests to monitor eradication.

According to our data, the level of specific anti-Helicobacter antibodies, according to ELISA results, was 1.305 and 0.669 in HP(+) and HP(-) children, respectively (p<0,001). Титр Ig G к НР нарастал в зависимости от тяжести морфологических изменений СОЖ. Так, у детей с неизмененной СОЖ титр Ig G составил 0,873, при поверхностном гастродуодените — 1,125, а при язвенной болезни 12-перстной кишки — 1,422 (р<0,05). Но, к сожалению, гуморальный ответ оказывается недостаточно эффективным в борьбе с инфекцией.

• lThe third stage of pathogenesis is reproduction, tissue damage, transmission to a new susceptible host. The result of the interaction between HP and the macroorganism depends not only on the degree of invasion and virulent properties of genetically heterogeneous strains of the pathogen, but also on the immunological reactivity of the child’s body. Cases of “healthy bacterial carriage,” as well as cases of self-healing in children, are apparently due to the peculiarities of the local immune defense of the coolant and the general immunological status of the child.

Recognition of the leading role of HP led to the creation of multicomponent anti-Helicobacter treatment programs aimed at eradicating the pathogen itself. Treatment regimens for adult patients, most of which are aggressive and unsafe for children, began to be automatically transferred to pediatric practice. Modern treatment programs for HP-associated diseases include a combination of two or three antibacterial agents and antisecretory drugs. A paradox arises: often much more severe and even life-threatening conditions are treated with fewer antibacterial drugs than HP. Today, even acute intestinal infections of mild and sometimes moderate severity are offered by infectious disease specialists to treat without antibiotics. In the case of HP infection, the pediatrician must understand that even successful eradication does not guarantee against reinfection. According to the literature, the risk of reinfection in children 6 months after successful treatment is quite high. At the same time, quite often, during anti-Helicobacter therapy, adverse reactions and complications occur in children: allergic and hepatotoxic reactions, disturbances of intestinal microbiocenosis, motor disorders of the upper gastrointestinal tract (GER, DGR). These circumstances often call into question the advisability of anti-Helicobacter therapy for all HP-infected children.

Finally, the effectiveness of eradication is constantly decreasing due to the rapidly increasing resistance of HP to the drugs used. This fact is associated with the pronounced instability and variability of the HP genome, as mentioned above, as well as with the widespread use of drugs included in treatment regimens for other indications.

In our work, we carried out a comparative analysis of the eradication effectiveness of various treatment regimens in HP(+) children (Fig. 3). The percentage of successful eradication when using the amoxicillin-metronidazole-de-nol regimen was 43%, and the amoxicillin-metronidazole-famotidine regimen was 50%. Replacing metronidazole with furazolidone in these regimens led to the fact that the eradication efficiency increased to 76%, which indicates the promise of using furazolidone in eradication programs. The use of only symptomatic therapy (antacids, cytoprotectors, prokinetics, physiotherapy) without the use of antibacterial agents led to recovery from HP in 37% of cases. The use of symptomatic therapy in combination with laser therapy on the epigastrium and biologically active points made it possible to achieve eradication in 75% of children. Thus, we did not obtain satisfactory eradication when using various options for “triple” therapy, apparently due to high drug resistance. The combination of symptomatic and immunomodulatory therapy made it possible to achieve results comparable to eradication regimens, but without the use of aggressive drugs. It should be noted that improvement in the clinical picture and epithelization of erosive and ulcerative defects of the gastric mucosa occurred at approximately the same time when eradication and alternative treatment programs were used.

In conclusion, it should be noted that, despite the active study of HP infection in recent years, many questions regarding the pathogenesis of the infectious process and methods of adequate treatment of HP-associated diseases in children await their final solution. Until then, the pediatrician must take a very balanced approach to prescribing eradication therapy for HP, guided by one of the commandments of Hippocrates: “Do no harm!”

Literature

1. Aruin L. I., Grigoriev P. Ya., Yakovenko E. P. Chronic gastritis. Amsterdam, 1993. 362 pp.
2. Domaradsky I.V. Issues of pathogenicity of Helicobacter pylori // Epidemiol. and infectious diseases. 2001. No. 2. P. 45-47.
3. Pasechnikov V.D., Mashentseva E.A., Zhurbina N.V. et al. Inflammatory and immune response of the gastric mucosa to H. pylori in peptic ulcer // Ross. journal gastroent., hepatol. and coloproct. 1998. T. V111. No. 3. pp. 41-45.
4. Zimmerman Ya. S. Gastroduodenal pathology and Helicobacter pylori // Klin. Pharmacol. and therapy. 1999. No. 2.
5. Zimmerman Ya. S., Zinattulin M. R. The concept of the relationship between the human body and Helicobacter pylori // Klin. medicine. 1999. No. 2. P. 52-56.
6. Ando T., Perez-Perez G. I., Kusugami K., Blazer M. J. et al. Anti-CagA immunoglobulin G responses correlate with interleukin-8 induction in human gastric mucosal biopsy culture // Clin and Diagn Labor Immunol. 2000. Vol. 7. No. 5. P. 803-809.
7. Bamford K. B., Fan X., Crowe S. E. et al. Lymphocytes in the human gastric mucosa during H. pylori have a T-helper cells 1 phenotype // Gastroent. 1998. No. 114. P. 482-492.
8. Blazer M. J., Berg D. E. et al. Helicobacter pylori genetic diversity and risk of human diseases // J. Clin. Investig. 2001. Vol. 107. No. 7. P. 767-773.
9. Blazer M. J. Helicobacter pylori and gastric diseases // Brit. Med. J. 1998. Spl 316. P. 1507-1510.
10. Camorlinga-Ponce M., Torres J., Perez-Perez J. et al. Validation of a serological test for the diagnosis of Helicobacter pylori infection and the immune response to urease and CagA in children // Amer. J. Gastroent. 1998. Aug 93 (8). P. 1264-1270.
11. Chavez E., Sanmiento F., Lopez M. et al. Interleukin-8 levels in gastric biopsies of children colonized by Helicobacter pylori // Rev. Med. Clin. 1998. Feb 126 (2). P. 139-142.

V. A. Alexandrova, Doctor of Medical Sciences, Professor
I. P. Kozlova
SPbMAPO, St. Petersburg

Note!

• HP infection is considered one of the most common in the world. It affects about half of the world's population, but chronic gastroduodenitis and peptic ulcers develop only in a portion of those infected.
• According to the literature, when a pure culture of HP is administered to volunteers, only one out of 8-10 people develops gastritis, and an experimental model of HP-associated peptic ulcer disease still does not exist.
• The presence of HP in the stomach is associated with an increased risk of developing peptic ulcers and adenocarcinoma, and the absence of HP is associated with a high risk of gastroesophageal reflux disease and its sequelae, Barrett's esophagus and esophageal adenocarcinoma.
• Apparently, HP can manifest its pathological properties only when the balance in the microecological system of the stomach is disturbed and the local immunological defense of the gastroduodenal mucosa changes.

The bacterium Helicobacter pylori (Helicobacter pylori) lives in the cells of the mucous membrane of the human stomach and duodenum. Some strains (genetic types) of the microorganism secrete specific toxins that destroy cells and increase the risk of pathologies such as chronic gastritis and duodenitis, gastric and duodenal ulcers, and some types of malignant tumors. Such strains must be promptly identified and treated. One way to determine Helicobacter pylori infection is to perform a stool test.

The mechanism for determining Helicobacter using stool analysis

PCR (polymerase chain reaction), cultural and immunological stool tests are direct research methods.
Unlike indirect methods, when the presence of a pathological agent is judged by the presence of its metabolic products or the reaction of the body's immune system (antibody production), direct methods directly detect the microorganism itself or its DNA.

All types of stool tests for helicobacteriosis are non-invasive (non-traumatic) types of research, unlike blood sampling or gastroduodenoscopy.

Molecular diagnostics

To carry out PCR, a special device is used - an amplifier.

The PCR method is one of the types of molecular genetic diagnostics and allows you to determine the presence of Helicobacter pylori even if a small fragment of bacterial DNA is present in the material.

The essence of the method is to repeatedly multiply the analyzed sample of the pathogen. To carry out the reaction, a kind of “framework” is required, consisting of two primers - obtained through artificial synthesis of DNA fragments identical to the nucleic acid of Helicobacter pylori. During the reaction between the primers, the DNA chain grows if a fragment of microorganism biomaterial is present in the feces. If it is absent, no reaction occurs.

The reaction is carried out at certain temperatures and acidity of the environment, consists of several dozen repeating cycles, and a special enzyme, polymerase, is used for catalysis (acceleration of the reaction). Over 30 cycles, the DNA fragment of the pathological agent present in the biomaterial is multiplied a billion times, which makes it possible to accurately diagnose the infection.

If appropriate primers are available, infection with cytotoxic (damaging cells of the gastric mucosa) Helicobacter pylori species can be detected.

Cultural analysis (bacteriological culture) is a microbiological research method.

Biological material is placed in a specific environment favorable for the growth of a bacterial colony. After a certain period of time (for Helicobacter pylori - more than a week), the culture is studied under a microscope, using various methods to correctly identify the colony - coloring, the ability to enter into certain biochemical reactions.

In addition to identifying the pathological antigen (the causative agent of the disease), the method allows you to test for its sensitivity to antibacterial drugs, which reduces the time and cost of treatment and increases the effectiveness of therapy.

Unfortunately, in some cases, the results of an in vitro sensitivity test (“in vitro”) may not coincide with the results of treatment in vivo (a living organism): in real life, antibiotics selected by a laboratory method may not be so effective.

Immunological methods of analysis

Immunological methods are based on the property of antibodies to stick to antigen. For research, antibodies with special labels are combined with the sample being analyzed, as a result, if Helicobacter pylori is present in the material, antigen-antibody complexes are formed.

Indications for examination

All types of diagnosis of Helicobacter pylori infection have their advantages and disadvantages. The advisability of using a particular method depends on various factors and stages of treatment. The optimal method of examination is chosen by a gastroenterologist.

Indications for PCR analysis of stool:

• ulcers, and duodenum;
• atrophy of the gastric mucosa;
• polyps, stomach tumors;
• gastroesophageal reflux (reflux of stomach contents into the esophagus), esophageal ulcer;
• genetic predisposition: malignant tumors of the stomach in close relatives (parents, siblings);

A PCR study is optimally prescribed to assess the feasibility of specific treatment with antibacterial drugs for existing organic damage.

Indication for cultural analysis is to determine sensitivity to drugs when empirical treatment is ineffective. Since the test is complex (culture requires a special environment and lack of oxygen) and long-term, this test is not prescribed to diagnose an infection.

Bacteriological culture is capable of isolating only spiral forms of Helicobacter pylori, but not coccal forms, which have recently become widespread. This fact further reduces the value of the study.

Indications for immunological methods:

• symptoms of functional and organic pathologies of the stomach and intestines:
  • , belching;
  • pain that occurs periodically throughout the day with exacerbations in spring and autumn;
  • diarrhea or constipation;
  • feeling of discomfort, fullness of the stomach;
• before prescribing long-term therapy with non-steroidal anti-inflammatory drugs or proton pump inhibitors (drugs to reduce the production of hydrochloric acid);
• iron deficiency anemia or thrombocytopenia of unknown etiology;
• genetic predisposition;
• infection of the immediate environment;
• monitoring the effectiveness of antibiotic therapy.

Immunological methods and PCR without genotyping are prescribed for screening purposes - due to its simplicity and relatively low cost, the study is carried out to the general public to identify groups at risk of developing organic and tumor lesions of the stomach and intestines.

Unfortunately, screening for Helicobacter pylori is not widespread in Russia.

Immunological analysis is carried out before instrumental research methods with appropriate symptoms and suggests infection with Helicobacter pylori. Based on the results of the analysis, if necessary, other research methods are prescribed.

Advantages and disadvantages of PCR analysis of stool

Specific therapy of helicobacteriosis with antibacterial drugs is a long process, accompanied by poor tolerability in many patients and a high risk of complications.

Prescribing antibiotics to everyone infected with Helicobacter pylori is a bad practice. Specific antibiotic therapy is indicated only for patients with a tendency to progression of organic lesions - erosions, ulcers, atrophic process - usually infected with certain strains of Helicobacter.

These patients require antibiotic therapy in order to achieve remission from peptic ulcers and prevent the risk of developing malignant neoplasms.

Cytotoxic types of Helicobacter pylori can only be detected using the PCR method.

• Advantages of PCR stool analysis:
• high sensitivity of the method;
• high specificity of the test;
• simplicity and non-invasiveness of material collection;
• safety;
• the ability to isolate different strains of bacteria.

Test sensitivity is the ability to produce true positive results. The higher the sensitivity, the lower the proportion of false positive results, when the antigen is allegedly detected in uninfected individuals.

The specificity of the test is an indicator that depends on the number of false negative (when the antigen is not released in an infected patient) test results. The PCR method for testing stool for Helicobacter pylori is characterized by a sensitivity of 64–94% and 100% specificity.

Collecting feces is easy and simple. Unlike blood sampling or gastroduodenoscopy, taking material does not require the use of local anesthetics, to which an allergic reaction can develop, does not cause pain or discomfort, and is safe in terms of contamination with a “dirty” instrument. The study does not require any special effort, such as the breathing method, which makes it accessible even to small children.

Disadvantages of PCR stool analysis:

• inability to determine sensitivity to antibacterial drugs;
• inability to distinguish between a current infection and a successfully cured one, when DNA fragments of the bacterium can remain in the feces for about a month;
• lower sensitivity compared to the study of a biopsy (tissue sample or cell mass) of the gastric mucosa;
• relatively high cost of analysis with genotyping;
• strict requirements for personnel: qualifications, strict adherence to rules, accuracy.

One of the main disadvantages of the PCR method is a continuation of its main advantage: the high sensitivity of the test causes false positive results in the event of contamination (“contamination” from the outside) of the analyzed material.

Preparing for the test

The reliability of the result of any analysis depends on the strict fulfillment of certain conditions at all stages, and sampling of material is no exception.

Rules for taking material:

• three days before the analysis, antibiotics, laxatives, drugs that slow down peristalsis, rectal suppositories and some other medications are discontinued according to the doctor’s instructions, so you should warn the doctor about the use of certain medications;
• Feces are collected in containers issued by the laboratory; it is recommended to take samples from three different points;
• It is advisable to deliver the biomaterial to the laboratory immediately; if this is not possible, the sample should be stored at a temperature of 2–8 degrees for no longer than 24 hours;
• if the test is performed to evaluate the effectiveness of previously prescribed antibiotic therapy against Helicobacter pylori, stool is collected no earlier than four weeks after the end of treatment.

Slowing the passage of feces and constipation can lead to the destruction of Helicobacter in feces, which causes false negative results. To increase the reliability of the result, the doctor may prescribe a mild laxative - lactulose - before the analysis.

How and where to get tested

The tests are prescribed by a gastroenterologist, so his consultation is necessary before testing for Helicobacter pylori.

Approximate cost of stool examination:

• PCR method with genotyping – 1200 rubles;
• PCR without genotyping – 600 rubles;
• sensitivity to antibiotics – 600 rubles;
• immunological methods – 400–650 rubles (depending on the method).

For the most accurate diagnosis of Helicobacter pylori, it is necessary to choose a medical institution that has earned a good reputation.

Research results

The processing time of tests and their reliability depend on the method of antigen determination.

Timing of completion, reliability and interpretation of stool test results for helicobacteriosis.

	Deadlines	Credibility	results
PCR	from 5–6 hours (express method) to 2 days	high	1) negative – not a single declared genotype of the bacterium has been identified; 2) positive – helibacteriosis (current or in history), at least one of the declared genotypes has been identified
Bacteriological analysis for sensitivity to antibiotics	7–10 days	high – for sensitivity; low – for antigen detection	1) number of bacteria 0 – Helicobacter was not isolated; 2) number >0 - helibacteriosis; 3) S – sensitivity to the specified antibiotic; 4) R – resistance (resistance) to the antibiotic; 5) I – moderate sensitivity to the antibiotic.
Immunological methods	1 day	low	1) negative - the pathogen has not been identified; 2) positive - helicobacteriosis

The low reliability of immunological and cultural analysis is explained by the low content of antigen in feces: if the PCR analysis is sensitive even in the presence of 10 cells, then for a reliable result of other methods there must be at least 10 times more cells.

Examination of stool for helibacteriosis is safe, non-traumatic and can be carried out using different methods to detect infection, determine virus strains and pathogen sensitivity to antibiotics.

Based on the test results, it is possible to form a risk group, whose representatives have a high probability of developing stomach and duodenal ulcers, and malignant stomach tumors; assess the degree of risk and minimize it by timely antibacterial treatment of cytotoxic strains of helicobacteriosis.

HELICOBACTER PYLORI INFECTION (HP)

EPIDEMIOLOGY, DIAGNOSIS AND TREATMENT METHODS

The etiological role of bacteria in the development of peptic ulcers has long been assumed. In 1893, people first started talking about the discovery of spirochetes in the stomachs of animals, and in the 1940s, these microorganisms were discovered in the stomachs of people suffering from peptic ulcers or cancer of this organ.

Only in 1983 was the presence of a pathogenetic connection between bacterial infection and peptic ulcer confirmed.

Researchers Robin Warren and Barry Marshall from Australia reported the presence of spiral-shaped bacteria, which they subsequently obtained in a culture medium, in patients with chronic gastritis and peptic ulcers. Initially, it was believed that these bacteria belong to the genus Campylobacter, however, they were later assigned to a separate, new genus. Since 1989, this microorganism has been called worldwide Helicobacter pylor (Hp).

BIOLOGY OF MICROORGANISM

HP- a gram-negative microaerophilic bacterium of a curved or spiral shape with many flagella. It is found deep in the gastric pits and on the surface of epithelial cells, mainly under the protective layer of mucus lining the gastric mucosa. Despite such an unusual environment, competition HP there are no other microorganisms.

The pH of the habitat, Hp, is approximately equal to 7, the oxygen concentration is low, and the nutrient content is quite sufficient for the life of the microbe.

VIRULENCE

Today, several virulence factors are known that allow Hp to colonize and then persist in the host body:

· Spiral shape and presence of flagella

· Presence of adaptation enzymes

Adhesiveness

· Suppression of the immune system.

Spiral shape and presence of flagella

The spiral shape of HP is well adapted to movement in the viscous layer of gastric mucus, which allows the microorganism to completely populate the mucous membrane. In addition, the presence of coated flagella allows for rapid movement in both gastric juice and mucus.

Adaptation enzymes

HP produces enzymes - urease and catalase. Urease, contained in gastric juice, catalyzes urea into carbon dioxide (CO 2 ) and ammonium ion (NH4+), which further neutralizes the pH of the immediate environment of the microbe and protects pH from the bactericidal effect of gastric hydrochloric acid. Thus, the microorganism, preserved in the gastric juice, penetrates the protective layer of mucus on the surface of the gastric epithelium.

The release of catalase, and possibly also superoxide dismutosmutase, allows HP to suppress the host's immune response. These enzymes catalyze the reaction of converting bactericidal oxygen compounds released by neutrophils activated as a result of infection into harmless substances such as oxygen and water.

Adhesiveness

The ability of HP to attach to the oligosaccharide components of specific phospholipids and glycoproteins on the membranes of gastric epithelial cells determines its selective colonization of these mucus-secreting cells. In some cases, adhesion leads to the formation of a characteristic structure called a “pedestal.” In those places where the membranes of bacterial cells are adjacent to each other, destruction of microvilli and rupture of cytoskeletal components are observed. Other possible receptors for Hp binding include extracellular matrix components, such as laminin, fibronectin, and various types of collagen.

It is assumed that only a very small part of the microorganisms (less than 10%) present in the stomach are in a bound state at any given time. There is no single point of view regarding the need for Hp adhesion, and even if adhesion is not a prerequisite for colonization of the gastric mucosa, then it, apparently, can be considered as an extremely important stage in the development of the disease.

Immune system suppression

HP stimulates the host's immune system to produce systemic antibodies. However, as research results have shown, microorganisms are capable of suppressing cellular immune responses.

The body's defense against infection is carried out by phagocytes, which are capable of capturing and digesting foreign substances, including bacteria. Under normal conditions, phagocytes cannot pass through the gastric mucosa, but if this nevertheless occurs, hemagglutinins located on the surface of Hp cells can inhibit the process of adhesion or phagocytosis by polymorphonuclear leukocytes. In addition, ammonia produced by HP can damage the membranes of phagocytes. As already noted, the activity of catalase Hp allows it to avoid the destructive effects of neutrophils.

Lipopolysaccharides (LPS) act as a hydrophilic barrier associated with the surface of bacterial cells. LPS HP were formed during evolution to protect against an overactive immune response, which allows the microorganism to survive in the stomach. LPS Hp taken from ulcer patients can stimulate the secretion of pepsinogen, leading to excess pepsin, which is a risk factor in the development of peptic ulcer disease.

Pathogenicity

There are several mechanisms by which HP causes the development of the disease:

· Toxins and toxic enzymes

· Stimulation of inflammation

Changes in gastric physiology

Toxins and toxic enzymes

Cytotoxins

About 65% of HP strains produce vacuolating cytotoxin (Vac A), which promotes the formation of vacuoles in epithelial cells, leading to their death. Almost all patients with duodenal ulcers are infected with the Bac A-forming strain Hp. Cytotoxic activity is higher in those microorganisms that were obtained from patients with duodenal ulcers, compared to those that were taken from individuals who did not suffer from peptic ulcers. Vac A-forming Hp strains also produce cytotoxin-associated protein (CagA). Antibodies to CagA were found in the serum of almost all patients with carcinoma and gastric ulcer.

Urease

In addition to being a virulence factor, urease activity may be associated with the toxic effects of the ammonia produced. At high concentrations, ammonia causes vacuolation of epithelial cells, similar to that observed when exposed to the vacuolating toxin Hp.

Phospholipases A2 and C

The membranes of gastric epithelial cells consist of two phospholipid layers. As a result of the action of phospholipases A2 and C produced by HP, changes are observed in them in vitro.

Phospholipases from bacteriolysates convert the hydrophobic surface of the phospholipid biolayer into a “wet” hydrophilic state. Thus, as a result of the action of these bacterial enzymes, the integrity of the membranes of epithelial cells and their resistance to damage, for example, to gastric hydrochloric acid, is disrupted.

Phospholipases can also disrupt the protective function of gastric mucus. The hydrophobicity and viscosity of mucus equally depend on the phospholipid content in it. In the presence of HP, mucus becomes less hydrophobic, and its viscosity decreases. These changes can lead to the fact that a large number of hydrogen ions enter the mucous membrane from the lumen of the stomach, which causes its damage.

Stimulation of inflammation

The inflammatory reaction that occurs in the host’s body in response to the introduction of Hp itself contributes to the disruption of the integrity of the gastric epithelium. Chemotactic proteins released by HP attract a large number of neutrophils, lymphocytes and monocytes. So, the presence of a large number of neutrophils in the gastric epithelium is typical for Hp infection. Mononuclear cells release interleukins, tumor necrosis factors and superoxide radicals. Interleukins and tumor necrosis factors do not allow mononuclear cells to migrate from the site of the inflammatory reaction. In addition, they trigger the formation of superoxide radicals, which are then converted into other active oxygen intermediate metabolites that are toxic to both HP and mucosal cells.

Other inflammatory mediators associated with Hp infection appear to be phospholipase A2 and platelet activating factor (PAF). Phospholipase A2 is involved in the breakdown of phospholipids in the cell membranes of the host organism, which leads to the formation of compounds that cause chemotaxis of inflammatory cells and also impair membrane permeability. PAF can also cause serious pathological changes, in particular gastric ulceration, and PAF precursors are found in gastric biopsies from patients with Hp-positive duodenal ulcers.

Changes in gastric physiology

Gastrin is a peptide hormone secreted by antral G cells. An increase in serum gastrin levels in patients with Hp-positive duodenal ulcers leads to an increase in acid secretion, either by a direct increase in the production of parietal cells or by an increase in the number of parietal cells.

An increase in the release of gastrin by the antrum of the stomach as a result of Hp infection occurs for the following reasons:

· Ammonia, formed under the influence of urease Hp, increases the pH of the mucous layer of the gastric epithelium, thus interfering with the physiological mechanism of negative feedback between the secretion of gastrin and hydrochloric acid of the stomach.

· Mucosal inflammation in Hp-infected individuals can stimulate gastrin secretion.

· Somatostatin, secreted by D cells of the antrum, inhibits the synthesis and secretion of gastrin by G cells. Studies conducted with Hp-infected individuals have revealed a decrease in the concentration of antral somatostatin.

The content of pepsinogen in the blood is also increased in Hp-positive patients with duodenal ulcers. Pepsinogen is produced by acid-forming cells of the mucous membrane of the fundus of the stomach and is secreted both into its lumen and into the blood. For the formation of the proteolytic enzyme - pepsin - activation of its precursor in the acidic contents of the stomach is necessary. An increase in serum pepsinogen I levels is an important risk factor for the development of duodenal ulcers, occurring in 30-50% of patients.

Epidemiology

Hp infection usually occurs in childhood and, if untreated, persists in the body indefinitely. The incidence of Hp infection among children 2 to 8 years of age in developing countries is 10% per year and reaches almost 100% by adulthood. In developed countries, the prevalence of HP also increases with age, but infection in children is relatively low.

In addition to age, an important epidemiological factor for HP is socioeconomic status. In general, the lower the socioeconomic status of the population, the higher the risk of infection. There is an assumption that the predominance of children in society is the only significant risk factor, while the provision of clean drinking water and compliance with sanitary standards are also important in the prevention of HP infection.

Based on the results of several studies, experts came to the conclusion that the prevalence of HP is influenced by occupational factors. Slaughterhouse workers (exposure to infected animals) and gastroenterologists have been shown to be high-risk groups.

2.6. Transmission routes

The natural reservoir of HP is primarily humans, but infection is also found in domestic cats, non-human monkeys and pigs. There are two possible routes of transmission: fecal-oral and, to a lesser extent, oral-oral.

Fecal-oral route

· Through contaminated drinking water (Hp can survive up to 2 weeks in cold sea and river water).

· When eating raw vegetables that are watered with untreated waste water.

Oral-oral route

· There is evidence of high survival rate of HP on dental plaque and in saliva.

· As a result of ingestion of vomit; HP can persist for some time in gastric juice.

· The least common is through insufficiently disinfected endoscopes and biopsy forceps (iatrogenic transmission route).

Reinfection

Recurrence of a duodenal ulcer after therapy aimed at eradicating HP is often associated with reinfection (re-infection).

From the results of studies of the frequency of reinfection during the first year after appropriate treatment (patients were re-examined every 12 months), it follows that it ranges from 0 to 35%. The annual reinfection rate tends to decrease to 3% or lower after the first year.

The higher rates of reinfection during the first year cited by a number of researchers can be explained by the fact that they observed a false reinfection, that is, an exacerbation of an “old” infection. False reinfection can be observed:

· When, after eradication therapy, a small number of microorganisms remain, but are not detected during a control examination.

· As a result of the retention of HP in other parts of the gastrointestinal tract (for example, on dental plaque, in saliva or feces), which leads to autoinfection of the stomach.

DISEASES ASSOCIATED WITH HELICOBACTER PYLORI

HPfound in persons suffering from the following diseases:

· Peptic ulcer (peptic ulcer; PU)

Gastritis

· Non-ulcer dyspepsia (NUD)

· Stomach cancer

Convincing evidence of a causal relationship between HP and the development of reflux esophagitis, as well as ulcers induced by taking non-steroidal anti-inflammatory drugs (NSAIDs), do not currently exist.

Peptic ulcer

From 90 to 100% of people with duodenal ulcers are infected with Hp.

Ulceration of the duodenum in HP- negative individuals are usually the result of taking NSAIDs or a manifestation of Zollinger-Ellison syndrome.

In case of gastric ulcer, infection HP approaches 85%. NSAID use is another important etiological factor of gastric ulcer. Prevalence of infection HP becomes even higher if we take into account only the subgroup of people with gastric ulcers who deny taking NSAIDs.

The most convincing evidence of the role HP in the pathogenesis of peptic ulcers there is a positive dynamics during the course of the disease after eradication therapy. Taking antisecretory drugs quickly and effectively heals ulcers, but a relapse occurs immediately after stopping their use.

The results of numerous studies confirm that after successful healing of a duodenal ulcer during the first 12 months, relapse is observed in approximately 80% of individuals, and 1-2 years after the end of treatment it reaches 100%.

After eradication therapy, relapse is observed in no more than 10% of individuals within 1 year after the end of therapy

Gastritis

Most often, exacerbation of chronic gastritis is associated with Hp.

In response to the implementation HP neutrophils migrate into intraepithelial and interstitial spaces, and lymphocytes, including plasma cells, also come here. In a biopsy obtained during an exacerbation of gastritis, when neutrophils are found in significant numbers, HP. This form of gastritis is most often localized in the antrum and has the most malignant course. In severe cases, the body of the stomach may also be involved in the process.

Non-ulcer dyspepsia (NUD)

NUD is defined as a recurrent feeling of discomfort in the epigastric region, often associated with eating without the presence of morphological signs of a peptic ulcer.

According to statistics, NUD affects 20 to 30% of the world's population.

Etiological role HP with NUD remains unclear, existing data on this matter are ambiguous. Numerous studies indicate a higher detection rate HP in persons with NUD compared with those without the latter. However, the reliability of the results of most of these studies is highly questionable due to the insufficient number of subjects studied in the control groups.

Stomach cancer

Between infection HP and the development of chronic gastritis there is a strong correlation. In chronic gastritis, gastric atrophy and intestinal metaplasia, which is a precancerous condition, are observed. However, the detection of Hp in gastric biopsies is very problematic due to severe gastric atrophy and intestinal metaplasia, in which it is impossible to maintain the population of the microorganism.

At the same time, epidemiological studies have shown that the prevalence HP often higher in regions with a high prevalence of stomach cancer.

From the results of prospective studies, it follows that in persons with serologically proven infection, the risk of developing stomach cancer is significantly higher.

Moreover, serological studies revealed the fact of infection HP in the past, a large number of stomach cancer sufferers. Due to the possible connection between infection HP and the development of stomach cancer in 1994, WHO experts included this microorganism in class 1 carcinogens (class of reliable carcinogens).

QUESTIONS FOR DIAGNOSIS AND TREATMENT

DIAGNOSTICS

Diagnostic tests aimed at identifying HP, are summarized in table 3.1.

There are two types of tests - invasive and non-invasive. To confirm the success of eradication therapy, these studies should be carried out no earlier than the fifth week after its completion

Invasive tests

All these studies require gastroscopy with a gastric biopsy, and there are three methods for detecting HP:

· cultural

· histological

· rapid urease test

Culture method

The presence of even one bacterium in a biopsy leads to the growth of several colonies, which allows an accurate diagnosis to be made. Bacterial cultures are incubated in a microaerobic environment at a temperature of 370 C for 10 days, after which microscopic or biochemical identification of the type of bacteria grown is carried out.

Histological method

Histological examination will allow an accurate diagnosis to be made, especially in combination with a culture method or a rapid urease test.

It must be borne in mind that the results of the studies depend on the experience of the specialist who conducts them. The specificity of histological examination depends on the presence of bacteria of other species in the biopsy specimen and on the number of bacteria HP.

The biopsy specimen is fixed in formalin. When using, for example, silver-containing dyes, in particular Warthin-Starry dye, both the tissue and the microorganism are selectively stained, which aids identification. In the case of microscopic examination of a biopsy specimen, several fields of view are usually examined. Studying more than one drug increases the sensitivity of the study.

Rapid urease test

Used as a screening method during an endoscopic examination, the urease test allows obtaining results within an hour.

When the biopsy is incubated for 24 hours, the sensitivity of the test increases.

The gastric biopsy is incubated in an agar medium containing urea. If present in the biopsy HP its urease converts urea to ammonia, which changes the pH of the medium and, therefore, the color of the indicator. Test system CLOtest™ ( Campylobacter- like Organism test, Delta West Ltd) allows you to perform a urease test.

Non-invasive tests

There are 2 types of non-invasive methods for identifying a microorganism:

· detection of antibodies to it in biological fluids

· urease test

ANTIBODY DETECTION HP

Antibodies produced in response to Hp infection can be detected in serum and plasma, saliva and urine.

This method is the most informative for determining infection with a microorganism when conducting large epidemiological studies. The clinical use of this test is limited by the fact that it does not differentiate a history of infection from the presence of HP at present.

There are several modifications of this test, namely ELISA (enzyme immunosorbent method), complement fixation reaction, bacterial and passive hemagglutination, as well as the immunoblotting method.

The list of commercial serological kits includes Quick Vue™ (Quidel Corporation), Helistal™ (Cortecs Diagnostics), Helitest Lab™ (Cortecs Diagnostics) and Pylori Tek™ (Bainbridge Sciences, distributed by Diagnostic Products Corporation).

UREASE TEST

Presence of infection HP in the stomach is determined by the activity of urease specific to this bacterium. The patient is orally administered a solution containing 13C or 14C labeled urea. In the presence HP the enzyme breaks down urea, as a result of which the exhaled air contains CO2 with a labeled carbon isotope (13C or 14C), the level of which is determined by mass spectroscopy or using a scintillation counter, respectively.

Table 3.1 Comparison of diagnostic value of detection tests HP

MethodAdvantagesFlawsApplication

CulturalBiopsy Accuracy of identification Antibiotic sensitivity can be determined in vitro The need for repeated examinations High cost The need for special media that require a lot of time to obtain results Taking the latest generation antibiotics or PPIs can lead to false negative results Establishing a diagnosis Clinical observation after eradication therapy

Histological Biopsy Availability "Gold standard" The need for repeated examinations High cost The need for special media that require a lot of time to obtain results Taking the latest generation antibiotics or PPIs can lead to false-negative results Establishing a diagnosis Assessing the condition of the gastric mucosa Follow-up after eradication therapy

PPI proton pump inhibitors

INDICATIONS FOR ERADICATION THERAPY

Currently identifying HP requires eradication therapy only if there are clear indications for it.

In February 1994, a consensus group of the National Institutes of Health (NIH) from the USA developed recommendations to limit the indications for eradication therapy in patients with peptic ulcer disease. Later, in 1996 in Maachtricht (Netherlands), these recommendations were modified.

· Patients with peptic ulcer disease and the presence of Hp require the prescription of antibacterial and antisecretory drugs both immediately after diagnosis and in case of exacerbation of the disease.

(Maintenance doses of antisecretory drugs are indicated for patients with a history of gastrointestinal bleeding). HP- infected persons with peptic ulcers who have been receiving antisecretory drugs for a long time or are refractory to them should also take antibacterial drugs.

· Eradication therapy is also desirable in patients with NUD after a complete differential diagnostic study

· Statement of the existence of a relationship with infection HP and stomach cancer requires further clarification.

There is no convincing evidence of a connection between infection HP and the development of reflux esophagitis, as well as ulcers induced by taking NSAIDs. However there are compelling reasons to assert that eradication HP reduces the risk of developing other complications of peptic ulcers, in particular re-bleeding.

When treating such patients, complete confidence is necessary. that eradication therapy was successful. This dictates the need for a control study 4 weeks and 6 months after its completion, as well as antisecretory therapy in maintenance doses.

In practice, if an adult patient with an uncomplicated duodenal ulcer is not taking NSAIDs, testing for infection HP makes no sense, since the result will invariably be positive.

It should also be noted that HP is not the only risk factor for the development of peptic ulcers. Below is a list of a few more of them:

· Increased stomach acidity

· Blood type I (0)

· Tobacco smoking

· Taking ulcerogenic drugs, such as NSAIDs

· Psychological stress

· Presence of concomitant diseases, for example chronic respiratory failure, chronic renal failure

· Hereditary predisposition

Thus, in addition to eradication therapy, lifestyle changes are necessary, in particular smoking cessation, and cessation of NSAIDs.

DRUGS USED IN ERADICATION THERAPY

If there are indications for eradication therapy, an antisecretory drug is usually prescribed in combination with an antibiotic, for the following reasons:

· Some are effective against HP antibiotics are less stable in an acidic environment, and their effect is potentiated by antisecretory drugs

· For ulcer healing, an appropriate environment is required, which is achieved by taking these drugs.

ANTI-SECRETORY DRUGS

Today there are three groups of antisecretory drugs: H2 receptor antagonists, proton pump inhibitors and PYLORID.

H2 receptor antagonists (AGRs)

The point of application of drugs in this group are cell membrane receptors, but they are also capable of suppressing acid secretion and increasing the pH of the gastric environment. They promote ulcer healing, but do not have antibacterial activity. In addition to Ranitidine (Glaxo Wellcome), famotidine (Yamanouchi, Japan) and Nizatidine (Lilly, USA) are used in eradication therapy.

· Proton pump inhibitors

Drugs in this group of powerful antisecretory drugs act directly on the parietal cells of the stomach. In experiments in vitro they had a very weak effect on HP. The most widely known drug in this group is Omeprozole (Astra, Sweden), but Iansoprozole (Takeda, Japan) and Pantoprazole (Byk Gulden, Germany) are also used.

· PYLORID (see below)

ANTIBIOTICS

A huge number of antibiotics have been tested for activity against Hp. The following is a list of proven effective antibiotics:

· Clarithromycin is a highly effective drug from the macrolide group; has acid resistance and is well absorbed from the gastrointestinal tract (GIT)

· Amoxicillin is a drug from the penicillin group, often used in eradication therapy; acid-stable, but less active towards HP than clarithromycin. For greater effect, it is combined with metronidazole or tinidazole

· Metronidazole, tinidazole

These antibiotics from the group of imidazoles have a similar chemical structure. Their bactericidal effect is manifested at low pH values, but a serious problem is the increase in resistance HP to antibiotics. Consequently, they are often used in combination with one or two antibiotics from other groups

Tetracycline

This drug is used in combination with at least one other antibiotic and most often instead of amoxicillin.

BISMUTH

Bismuth salts, especially subsalicylate (Peptobismol™, Procter & Gamble, USA) have long been used to relieve symptoms of dyspepsia. Bismuth has a weak effect on Hp. The antimicrobial activity of bismuth salts is explained by their water solubility. Their other advantages are the ability to heal the gastric mucosa and their protective properties. When taking bismuth, temporary darkening of the tongue and stool may occur. In the mid-1970s, rare cases of encephalopathy caused by bismuth were observed, mainly in France and Australia, where the drug was prescribed for a long time and in high doses - significantly higher than those needed to eradicate Hp.

Colloidal bismuth subcitrate (CBS, De-Nol) is another bismuth salt that allows, in combination with two antibiotics, and sometimes also with an antisecretory drug, to achieve eradication in an acceptable number of cases HP.

ANTIBIOTIC RESISTANCE

Antibiotic resistance HP becomes a serious problem in eradication therapy. Resistance can be divided into primary (internal) and secondary (acquired):

· Primary caused by strains HP resistant before the start of eradication therapy

· Secondary involves resistance that has developed during unsuccessful eradication therapy

Resistance to metronidazole has been associated with treatment failure. There is marked geographic variation in the incidence of resistance to metronidazole, reflecting the varying breadth of use of this drug in different countries. Research data suggests that resistance HP use of metronidazole in the world is growing and in some countries it can reach figures of over 80%.

Sustainability HP to other antibiotics, including clarithromycin, was also detected, but to a lesser extent (for clarithromycin in Western Europe it is 5-10%).

PYLORID

NEW CHEMICAL COMPOUND

PYLORID (ranitidine bismuth citrate) is a new chemical compound with a unique combination of properties:

· Activities regarding HP

· Suppressing acid secretion in the stomach

· Protective properties in relation to the gastric mucosa

PYLORID has unique physicochemical properties that differ from the properties of a simple mixture of ranitidine hydrochloride and bismuth citrate. Thus, PYLORID is different

· Physico-chemical properties

· Biological properties.

PHYSICOCHEMICAL CHARACTERISTICS

The physicochemical properties that significantly distinguish PYLORID from a simple mixture of ranitidine hydrochloride and bismuth citrate are as follows:

· Melting temperature

· Spectroscopic parameters (in particular the nature of diffraction and spectra of nuclear magnetic resonance, NMR)

· Water solubility - bismuth citrate alone or in the presence of ranitidine hydrochloride is practically insoluble in water. PYLORID is completely dissolved at pH 4.

BIOLOGICAL PROPERTIES

The biological properties that distinguish PYLORID from a mixture of ranitidine hydrochloride and bismuth citrate are its activity towards

HPand suppression of pepsin formation

Activity regarding HP

The minimum inhibitory concentration (MIC) of PYLORID with respect to Hp is approximately half that of an equimolar mixture of ranitidine hydrochloride and bismuth citrate (Table 4.4).

The increase in antimicrobial activity of the drug is associated with the solubility of bismuth salts.

Table 4.4 Comparison of the activity of ranitidine bismuth citrate and a mixture of ranitidine hydrochloride and bismuth citrate in vitro in relation to 14 strains HP

TreatmentGeometric mean MIC a (mg/l)

Ranitidine bismuth citrate 12.5

Bismuth citrate 20.2v

Ranitidine hydrochloride + bismuth citrateb 25.7v

aConcentration of bismuth ions; b in concentrations equimolar to those in ranitidine bismuth citrate; vr<0,01 по сравнению с ранитидином висмута цитрата

SUPPRESSION OF PEPSIN FORMATION

Pepsin, an enzyme involved in the breakdown of proteins, is considered an important factor in the development of peptic ulcers. Human pepsin exists in several isomeric forms, with pepsin 1 being called ulcerogenic pepsin. In experiments in in vitro PYLORID significantly inhibits the activity of pepsin. (Fig. 4.5).

A suspension of ranitidine and bismuth citrate, alone or in combination with each other, does not have a significant effect on any of the pepsin isoenzymes.

BISMUTH

Due to the presence of bismuth in PYLORID, this drug has an antibacterial effect against Hp and reduces the activity of pepsin ( in vitro), and also, according to a mechanism that is not yet clear, has a protective effect on the gastric mucosa. PYLORID was developed with the expectation that when dissolved in the stomach, it provides a high concentration of bismuth in the stomach.

The absorption of bismuth when taking the drug orally is 0.5% of the dose taken, the rest passes unchanged through the gastrointestinal tract.

At the end of PYLORID therapy, the bismuth content in the blood serum is negligible and significantly less than the MIC for HP, which indicates its local rather than systemic action.

SYNERGY WITH CLARITHROMYCIN

Synergism is said to occur when the effect of the combined use of drugs exceeds the sum of the effects of each of them separately. Research in vitro showed that the combination of PYLORID with clarithromycin has synergism in demonstrating a bactericidal effect against Hp. It turned out that with the combined use of these drugs it lasts 24 hours.

RESISTANCE TO CLARITHROMYCIN

The use of PYLORID increases the bactericidal activity of clarithromycin against Hp strains resistant to this antibiotic.

In research in vitro It has been shown that the bactericidal activity of the combination of PILORID with clarithromycin against bacterial strains resistant to clarithromycin is 1000 times higher than with the isolated use of PILORID. Thus, PYLORID is a synergist with clarithromycin, even against strains resistant to it HP.

CLINICAL EVIDENCE OF THE EFFECTIVENESS OF PYLORID

5.1 HEALING OF DUODENAL ULCERS

PYLORID promotes effective healing of both gastric and duodenal ulcers.

Taking PYLORID effectively promotes the healing of duodenal ulcers. In a study designed to determine the optimal dose of the drug, it was shown that taking PYLORID at a dose of 400 and 800 mg 2 times a day for 4 weeks was more effective than taking 200 mg 2 times a day or taking ranitidine hydrochloride at a dose of 150 mg 2 times a day. There was no advantage of the 800 mg dose over the 400 mg dose.

HEALING OF STOMACH ULCERS

PYLORID is effective in treating stomach ulcers. When comparing the results of patients taking PYLORID at a dose of 200, 400 and 800 mg 2 times a day compared with taking 150 mg of ranitidine hydrochloride for 8 weeks, it turned out that doses of 400 and 800 mg 2 times a day were significantly more effective than a dose of PYLORID 200 mg 2 times a day or 150 mg of ranitidine hydrochloride 2 times a day.

Hp ERADICATION USING PYLORID IN COMBINATION WITH CLARITHROMYCIN

There were 4 clinical trials, each of which was multicenter, randomized, double-blind, and had parallel groups of patients.

Consistently high levels of eradication of the microorganism (82-94%) were achieved as a result of taking PILORID at a dose of 400 mg 2 times a day in combination with clarithromycin in Europe - 250 mg 4 times a day, in the USA 500 mg 3 times a day).

In both studies conducted in Europe, there was no benefit from taking PYLORID 800 mg twice daily compared with 400 mg twice daily (both in combination with clarithromycin).

Two additional studies have recently been completed comparing the effectiveness of different doses of clarithromycin in patients with duodenal ulcers. In both cases, patients received PYLORID 400 mg twice daily for 4 weeks in combination with clarithromycin 250 mg four times daily or 500 mg twice daily for the first weeks of treatment. One of the studies included a third group of patients who, in addition to clarithromycin at a dose of 500 mg 2 times a day, took metronidazole at a dose of 400 mg 2 times a day for the first 2 weeks.

In the first study, the effectiveness of a dose of clarithromycin 500 mg 2 times a day in relation to eradication of the microorganism was comparable to a dose of 250 mg 4 times a day and was 96% and 92% respectively.

In the second study, as a result of two doses of PILORID and clarithromycin 500 mg each, eradication was achieved 93% , which is significantly higher than in the case of taking clarithromycin at a dose of 250 mg 4 times a day (84%), and equivalent effectiveness of a triple regimen including metronidazole.

A double dose of PYLORID and clarithromycin at a dose of 500 mg allowed eradication of Hp in 96% cases.

RELIEF OF DISEASE SYMPTOMS USING PYLORID IN COMBINATION WITH CLARITHROMYCIN

Taking PYLORID in combination with clarithromycin for 2 weeks, followed by switching to PYLORID monotherapy for another 2 weeks, ensured the disappearance of the patient's complaints.

COMBINATION WITH AMOXICILLIN

Clarithromycin is the drug of choice in combination eradication therapy with PYLORID.

In the absence of clarithromycin, Piloride can be combined with amoxicillin, although the effectiveness of this combination is certainly lower. At the same time, the eradication frequency HP comparable to that when used with omeprozole. Recently, schemes using two antibacterial agents and PYLORID have attracted great interest. See below for the results of their use.

CLINICAL SAFETY

In controlled clinical trials, PYLORID was well tolerated.

The safety profile of the drug was comparable to that of patients taking placebo and ranitidine hydrochloride. There was no increase in the incidence of side effects when the drug was combined with clarithromycin or amoxicillin compared with those who took PYLORID alone. The only thing that patients noted, as would be expected in the case of taking bismuth-containing drugs, was blackening of the stool and, less often, blackening of the tongue.

Regimens used for HP eradication

GOLD STANDARD

The “gold standard” in Hp eradication was previously considered to be a combination of colloidal bismuth subcitrate (for example De-Nol), prescribed for 4 weeks, with antibacterial drugs (amoxicillin and metronidazole or tetracycline), prescribed during the first two weeks of treatment. This regimen has shown high effectiveness in removing Hp, but it cannot be considered ideal due to the high incidence of side effects and a complex drug regimen, which can lead to patient refusal of treatment.

TWO-COMPONENT SCHEME

When searching for optimal treatment regimens (high efficiency with a low incidence of side effects and ease of administration), two-component regimens were studied. The results obtained using the combination of omeprazole and amoxicillin were very contradictory. Hp eradication rates ranged from 0 to 92% (average 60%). However, among experts there is a growing opinion that omeprazole in combination with amoxicillin does not provide a high rate of eradication of the bacterium.

Other two-component regimens are the combination of PILORID with clarithromycin and the combination of omeprazole with clarithromycin.

· the combination of PYLORID with clarithromycin showed effectiveness in 82 - 96% of cases, which is comparable to the effectiveness of three-component regimens.

· The combination of omeprazole with clarithromycin showed significantly lower effectiveness (average 66%).

THREE-COMPONENT SCHEME

Recently in Europe there has been a trend towards the use of shorter courses of treatment aimed at eradicating HP. The MATCH-1 study compared five different combination regimens of omeprazole with two antibiotics, showing effectiveness in 79 - 96% of cases. These treatment regimens have been registered in several European countries and other parts of the world.

Literature review

Below are the most widely used regimens aimed at eliminating HP. It should be noted that in addition to differences in dosage and duration of treatment, studies have population differences, different diagnostic techniques (types and number of tests performed), and different analytical methods used to calculate elimination rates.

· Monotherapy

Clarithromycin1000 -20001411 - 5434

SWR*480 - 72014 -2819 -3325

Amoxicillin50 -150014 - 280 - 2813

SSV**900 - 210021 - 420 - 5610

Omeprazole20 - 4014 - 280 - 174

Lansoprazole30 - 6014 - 560 - 103

Ranitidine30028 - 560 - 41

*SWS - colloidal bismuth subcitrate; **Bismuth subsalicylate

· Two-component circuit

Drug Daily dose (mg) Duration (days) Eradication level (%) Generalized data (%)

Omeprazole + Clarithromycin20 -40 1000 -150014 - 28 1427 - 8866

Ranitidine + Clarithromycin300 - 1200 1000 - 200012 - 14 12 - 1450 - 8470

Metronidazole + Amoxicillin1000 - 2000 50 0 - 20005 - 30 7 - 3056 - 8068

SWR + metronidazole480 600 - 15007 - 5638 - 9168

Omeprazole + amoxicillin20 - 40 1500 - 200014 - 28 140 - 9260

Ranitidine + amoxicillin300 - 1200 200010 - 14 10 -1432 - 6557

· Three-component scheme

Drug Daily dose (mg) Duration (days) Eradication rate (%) Generalized data (%)

Omeprazole + Clarithromycin + metronidazole 40 1000 -1200 500 -100014 - 28 7 - 14 7 - 1486 - 92 89

SWR* + metronidazole + tetracycline480 600 - 120014 -28 7 - 14 7 - 1440 -9486

Omeprazole + metronidazole + Amoxicillin20 - 40 800 - 1500 1500 - 300014 - 28 7 - 15 7 - 1543 - 9577

Ranitidine + metronidazole + Amoxicillin300 - 1200 100 - 1500 1500 - 225021 - 42 12 - 14 12 - 1444 - 8878

SWR + metronidazole + Amoxicillin480 750 - 2000 1500 - 225014 - 28 7 - 14 7 - 1543 - 9577

SWR + tinidazole + amoxicillin4801000 1000 - 300010 - 28 7 - 13 7 - 1359 - 8370

One-week three-part regimen

omeprazole + amoxicillin + clarithromycin 20 - 40 1500 - 2000 500 - 1000776 - 10089

Omeprazole + metronidazole + clarithromycin20 - 40 800 500 - 1000779 - 9689

SWR + metronidazole + tetracycline480 1200 - 1600 1000 - 2000771 - 9486

Omeprazole + metronidazole + amoxicillin40 800 - 1200 1500 - 2000 778 - 9183

SWR + Omeprazole + clarithromycin480 20 - 40 500 - 1500740 - 9277

Omeprazole + tinidazole + Clarithromycin20 - 40 1000 500 - 1000750 - 9576

What is the effectiveness of the combination Pilorid + clarithromycin?

Drug daily dose (mg) duration (days) Eradication level (%) Generalized data (%)

PYLORID + clarithromycin 800 1000 - 150014 - 28 1482 - 9690

What is the effectiveness of the combination of Pilorid with other antibiotics?

Drug daily dose (mg) duration (days) Eradication level (%)

Piloride + clarithromycin + amoxicillin800 1000 -1500 1500 - 20007 - 1496

Pyloride + tetracycline + metronidazole800 1000 1000 - 12007 - 1488

Pilorid + clarithromycin + metronidazole800 500 1000786

INFLUENCE ON THE ULCER PROCESS

Considering that most publications are devoted to HP, it should be recalled that eradication therapy should be aimed not only at destroying the pathogen, but also at healing the ulcer and relieving the symptoms associated with it. Therefore, it is recommended to continue antisecretory therapy for 4 weeks for duodenal ulcers and for 8 weeks for gastric ulcers.

The ideal eradication therapy can be considered therapy that meets the following requirements:

· Consistently high level of HP eradication

· Simple reception mode (convenience)

· Low incidence of side effects

· Economical

· Minimal impact of resistant strains on eradication rates

· Effective effect on the ulcerative process.

It is believed that eradication therapy will replace short or long courses of antisecretory drugs as the preferred therapy in most patients with peptic ulcer disease. Doctors are gaining experience in using eradication therapy, and increasingly, treatment is prescribed empirically (without laboratory confirmation of the diagnosis). The need for drugs that not only have high activity in relation to HP, but are also convenient to take, quickly relieve symptoms, while having minor side effects, is rapidly increasing. There is no doubt that PYLORID will take its rightful place in the treatment of gastrointestinal diseases associated with HP infection.

Helicobacter pylori (Hp), gastric Helicobacter- These are spiral-shaped gram-negative bacteria, 3 microns in length, with a diameter of about 0.5 microns. The bacterium has 4-6 flagella and is able to quickly move along the gastric mucosa. Coccal forms of bacteria have been found in water bodies of various countries. Infection occurs from person to person.

Infection with H. pylori (Hp) of the stomach is the cause of 100% of cases of chronic antral gastritis, 95% of cases of duodenal ulcers, 80-90% of cases of benign non-drug gastric ulcers, MALT lymphomas of the stomach, 70-80% of cases of non-cardiac gastric cancer. Helicobacteriosis of the stomach is the presence of H. pylori (Hp) infection in the stomach.

The presence of HP infection in the stomach contributes to the progression of chronic gastritis, including asymptomatic gastritis, with the development of dynamic atrophy of the gastric mucosa (precancerous condition) and subsequently intestinal metaplasia and dysplasia (precancerous changes) in the gastric mucosa, and then gastric cancer .

In connection with the above, the diagnosis of H. pylori (Hp) of the stomach is given great importance in gastroenterological practice, as is the eradication of Hp (destruction and removal of Hp from the stomach).

Helicobacter bacteria (microorganisms) enter with infected products, water into the stomach and are stored on the gastric mucosa. During the period that Helicobacter is in the stomach, inflammation of the mucous membrane persists with the probable development of erosive and ulcerative lesions of the mucous membrane of the stomach and duodenum. In this case, Helicobacter bacteria (Helicobacter, Helicobacter pylorus) can be a trigger factor in the development of precancer (atrophic gastritis with metaplasia, dysplasia) of the stomach. When Helicobacter pylori (Hp) enters the stomach, it adapts to life on the gastric mucosa. Helicobacter pylori (Hp) is a risk factor for the development of gastric and duodenal ulcers, precancerous gastric pathology (atrophic gastritis, metaplasia, dysplasia) leading to gastric cancer (a long-term process).

Thus, the long-term presence of pyloric Helicobacter in the stomach (above the mucous membrane) successively triggers the processes: chronic inflammation, gastritis, atrophic gastritis, stomach cancer or the processes: chronic inflammation, gastritis (gastroduodenitis), stomach ulcer (duodenal ulcer).

Helicobacter pyloric bacteria have an even more damaging effect on the gastric mucosa (development of erosions, ulcers, bleeding) when the patient uses non-steroidal anti-inflammatory drugs (diclofenac, etc.), aspirin, hormones and other drugs.

Diagnostics Helicobacter pylori infection is usually done by asking the patient for the presence of dyspeptic complaints and symptoms and then performing tests that confirm or refute the presence of infection:

1. Bacteriological method. An imprint smear is taken from the surface of the stomach or intestines and examined under a microscope. The method has a wide range of sensitivity for Helicobacter, because in the case of a small concentration, not a single colony may reach the smear.

2. Serological method. In this case, enzyme immunoassay is used. Antibodies to Helicobacter, which are produced in the blood, are being studied.

3. Morphological method. It consists of examining a biopsy area that is stained with special dyes.

4. Stool examination. Helicobacter is being searched for in feces using enzyme immunoassay.

5.Polymerase chain reaction.

6.Biochemical methods. They are express methods and currently the most popular. Sufficiently high sensitivity in determining the microbe. The first of them is a urease test for examining a biopsy specimen. This is a special test produced commercially, in which a section of the stomach is placed and a reaction is automatically performed. The second test is breathing. It is based on exhaling air into a special bag after taking urea. The sensitivity of this method is one of the highest.

Preparing the patient for the urease breath test.

In order to correctly perform a urease breath test and obtain a reliable result, you must follow a few simple rules:

1. The study is performed strictly on an empty stomach and in the morning. A light dinner is possible the day before, no later than 22-00. It is possible to drink water no later than 1 hour before the test and no more than 100 ml.

2. The test is not performed if the patient is taking antibiotics, antisecretory, anti-inflammatory drugs, antacids and analgesics. The study can be performed 2 weeks after completion of taking antisecretory drugs and antibiotics. After taking the rest of these medications, the break should be at least 5 days.