|
|
Resistance to antimicrobial therapy of Helicobacter pylori strains
Moravcová, Monika ; Keil, Radan (advisor) ; Nyč, Otakar (referee)
Helicobacter pylori (hereinafter referred to as H. pylori) is a gram-negative bacteria which colonises the human stomach mucosa. Its role in the aethiopathogenesis of chronic gastritis, ulcer disorders of the gastroduodenum and MALT-lymphoma has been clearly demonstrated, and in connection with the occurrence of stomach cancer it has been indicated by the World Health Organisation (WHO) as a class I carcinogen. H. pylori infection can be detected from samples of stomach mucosa taken in an endoscopic examination (rapid urease test, microscopic examination, culture), or the non-invasive method can be used (13 C-Urea Breath Test or H. Pylori stool antigen test - HpSA). Effective therapy of H. pylori infection resides in the administration of a combination of antibiotics and a proton pump inhibitor. In recent years the resistance of bacterial strains to used antibiotics has been increasing on a worldwide scale, and we can also observe this trend in the case of H. pylori. If the level of resistance exceeds 20 % for clarithromycin and 40 % for metronidazole, these antibiotics are not recommended for the treatment of an infection caused by this bacteria. In a group of 61 patients at the Department of Internal Medicine at the University Hospital Motol who had undergone an endoscopic examination of the...
|
|
|
Ways to test for Helicobacter and calprotectin
LAVIČKOVÁ, Lucie
H. pylori is a gram-negative rod bacteria of a spiral shape. It is obligatory microaerofile. It has strong urease activity. It colonize the stomach mucosa and it is proved, that almost the half of human population is colonized. H. pylori concluding other factors can cause gastritis which can become chronic. Other diseases can be influenced by chronic gastritis - for example: gastroduodenal ulcer disease and stomach adenocarcinoma. H. pylori is concerned to be carcinogen of the first class. Calprotectin is a cytosol protein. It gradually releases from activated or lytic leucocytes. It is made of monocytes and neutrophiles. Calprotectin concentration in in faecal specimen correlates with the amount of leucocytes in intestine's lumen. This finding allows doctors to estimate the amount of intestine mucosas' infiltration by leucocytes according to evaluation of calprotectin levels. Calprotectin is highly sensitive to the presence of intestine inflammation, so it is a proper indicator of unspecific intestine inflammation diagnostics. The main aim of my bachelor thesis is to become familiar with identification methods of H. pylori and calprotectin in labs. Moreover, I aimed to become familiar with proper results interpretation of used methods. I estimated a hypothesis and an experimental question. In the theoretical part I focused on contemporary knowledge about H. pylori a calprotectin. I described common diagnostic methods, illnesses they cause and their treatment. The experimental part took place at Microbiology department of Stafila spol. sro laboratories. I examined the presence of H. pylori in faecal specimen by DIMA method. I determined the calprotectin levels by BUHLMANN method. I personally worked with 25 samples. I did my work in guidance of MUDr. Cihlová and her colleagues. I statistically examine my results. I made statistics of H. pylori frequency and determined the hypothesis. I also made statistic of negative, positive and strongly positive numerosity levels of calprotectin in faecal specimen and found the answer to my question.
|
|
|
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.
|
|
|
Laboratory diagnosis of Helicobacter pylori
OBERMAJEROVÁ, Jana
Helicobacter pylori is a Gram-negative, microaerophilic bacterium requiring for its growth and development a microaerophilic environment and carbon dioxide. The most important biochemical properties include the production of urease, catalase, alkaline phosphatase, and phospholipase as well as other enzymes. Helicobacter pylori colonises the gastric mucosa in the area of the antrum and may be transferred into the body of the stomach (Corpus gastricum) in the event of massive infection. It contributes to the development of gastric mucosal inflammation, especially the antrum mucosa, which later, in the majority of cases, passes to the chronic stage. It also contributes considerably to the development of both duodenal and gastric peptic ulcers. The connection between carcinoma and gastric MALT lymphoma has been proved. Diagnosis of Helicobacter pylori infection can be made by invasive and non-invasive methods. In order to proceed to the invasive method, a biopsy sample of the gastric mucosa must be taken. This sample is later submitted for histological and microbiological examination. The microbiological methods include microscopic examination, rapid urease test and H. pylori cultivation test. In principal, non-invasive methods (breath test, stool antigen test) are used for the verification of eradical infection treatment. The topic of the thesis dealt with the comparison of individual microbiological examination methods ? microscopy, cultivation and rapid urease test which are used at the Bacteriology Institute of Hospital of České Budějovice, a.s. in order to diagnose Helicobacter pylori. Biopsy samples of the gastric mucosa sent to the Bacteriology Institute in 2011 were used as the main material for the given study. The samples were most frequently taken at the Gastroenterology Department and Children´s Department. Each biopsy sample was divided into three parts for individual methods. A microscopic preparation was elaborated from a part of the sample. The stain device - MIRASTAINER? system was used for the Gram staining. During observations in the optic microscope (immersion lens system with 1000×) fine S-shaped Gram-negative rods were visible in the event of a positive finding. Other parts of the sample were used for the urease hydrolyses test (Christensen´s) in the liquid media. The test was assessed the following day, in the case of a positive finding the media went red. The remaining part of the sample was used for the cultivation examination. The material was inoculated into the HPFA diagnostic cultivation media provided by the Dulab Company and, at the same moment, on non-selective blood agar (in order to exclude contaminating microflora). The cultivation was executed in a microaerophilic atmosphere (obtained in the LAS system) from 5 to 7 days at 37 °C. In the event of a positive cultivation finding (often represented in case of H. pylori by typical, finer, slightly grey and partially transparent colonies) the sensitivity to antibiotics was tested. In 2011, the Bacteriology Department at the Hospital of České Budějovice, a.s. examined 599 biopsy samples of the gastric mucosa. The examination proved the presence of Helicobacter pylori infection in the bodies of 161 patients. The results of the study reveal that the sensitivity of the cultivation examination is comparable to microscopy. The lowest sensitivity was proved in the case of the urease test. The infection was the most commonly diagnosed in the age group between 40 and 59 years (47.5 % of men and 52.2 % of women). The sensitivity to selected antibiotics was determined in the case of 137 phyla. 42 % of phyla were resistant to metronidazole and 18 % of phyla to azithromycin.
|
|
| |
|
| |
|
| |
|
| |
|
| |
|
| |
guest ::
