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Diagnosis and therapy of Helicobacter pylori infection
POSPÍŠILOVÁ, Michaela
H pylori is a Gram-negative, microaerophilic rod-shaped moving bacterium, notorious for its urease production. It colonizes gastric mucosa and always leads to chronic gastritis, which may result in the development of other serious diseases, such as gastroduodenal ulcer disease and gastric adenocarcinoma. In 1994, H pylori was classified as a category 1 carcinogen. H pylori infection can be tested for invasively and noninvasively. The invasive methods include cultivation, histological examination and a rapid urease test. Noninvasive options are the carbon urea breath test, a stool antigen (HpSA) test and a blood antibody test. H pylori is sensitive to betalactam antibiotics. These should therefore be the essential part of the treatment; the instances of resistance are rare. Should the patient be allergic to betalactam antibiotics, nitroimidazoles can be used instead. H pylori is also sensitive to macrolides. The objective of my bachelor thesis was to acquire practical knowledge necessary for the correct processing of stool and serum samples in laboratory practice. I also intended to describe current trends in diagnosis and treatment of H pylori infection, together with the infection rates depending on age, sex and the season of the year. The findings were discussed in the context of relevant academic literature. Finally, I monitored the ways in which gastroduodenal ulcer disease caused by H pylori infection is diagnosed and treated by gastroenterologists in České Budějovice. The collection of the data for quantitative research was carried out between 1 January 2012 and 31 December 2012 in the microbiological laboratory Synlab czech s.r.o. in České Budějovice, which covers the whole of the South Bohemian Region. The samples were supplied mostly, but not exclusively, by GPs, and two methods of medical examination (euroSCREEN HP and EIA Helicobacter MONO IgG) were used. EuroSCREEN HP is based on the stool antigen (HpSA) detection, EIA Helicobacter MONO IgG is an immunoenzymatic method detecting IgG antibodies against H pylori in human serum or plasma. The data for qualitative research were collected in gastroenterologic ambulances in České Budějovice. Guided semi-structured interviews were carried out with one doctor in each ambulance. The acquired data were then processed as case studies and used to obtain categorization tables. The quantitative research confirmed all three hypotheses subject to evaluation. Higher age groups were found to have higher infections rates. However, no effect of either sex or the season of the year on the infection rates was registered. The qualitative research showed that gastroduodenal ulcer disease is most frequently diagnosed by České Budějovice gastroenterologists by the means of a biopsy check during gastroscopy. The samples are then sent to a microbiological laboratory for cultivation, histological examination and a rapid urease test. H pylori infection is usually treated by the standard triple therapy: amoxicillin, clarithromycin and a proton pump inhibitor. In case of hypersensitivity to betalactam antibiotics clarithromycin, a proton pump inhibitor and metronidazole are used instead. Occassional resistance to metronidazole and clarithromycin was reported. In these situations, cultivation is carried out in order to determine the sensitivity to antibiotics. The effects of the eradication treatment are evaluated by the means of a biopsy check during gastroscopy 6-8 weeks after its application. The samples are analysed in a microbiological laboratory. Some gastroenterologists also use a stool antigen (HpSA) test.
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