Patient factors affecting culture of Helicobacter pylori isolated from gastric mucosal specimens.

PURPOSE: Culture is one of the methods used for detecting Helicobacter pylori in the stomach. However, since it is costly, labor-consuming, and in a number of infected subjects gives a false negative result, the procedure is not routinely used. The aim of the study was to analyze some of the factors that may affect the outcome of H. pylori culture from endoscopic gastric mucosal specimens. MATERIAL AND METHODS: The study was conducted in a group of 265 subjects. The culture of gastric mucosal specimens was verified by urease test and histological examination. If the culture result was not consistent with one or two verifying tests, an additional two tests were used, i.e. H. pylori antigens in stool samples and anti-H. pylori antibodies in blood serum. RESULTS: In patients infected with H. pylori (at least two positive diagnostic tests), the analysis of factors that may affect the culture outcome revealed that neither age, gender, smoking, history of eradication, endoscopic diagnosis, use of proton pump inhibitors, ultrasonography of the abdomen or chest radiology performed the day before or on the day of gastroscopy, nor preparation for colonoscopy using osmotic fluids 1-2 days prior to gastroscopy had an effect on the culture outcome. Only high activity of gastritis (neutrophil infiltration) and low bacterial load in gastric mucosal specimens as well as drinking alcohol and the use of histamine H2 receptor blockers reduced culture efficacy in infected subjects. CONCLUSIONS: High activity of gastritis, low bacterial load, drinking alcohol and the use of histamine H2 receptor blockers can be the cause of failed H. pylori culture from gastric mucosa in the infected subjects. These factors should be taken into consideration when qualifying patients for the test and interpreting the results.

Application of immunoassay for detection of Helicobacter pylori antigens in the dental plaque.

PURPOSE: The aim of this study was to determine the viability of the commercial test currently used for detection of H. pylori antigens in the stool for detection of H. pylori antigens in dental plaque. MATERIALS AND METHODS: A total of 164 dyspeptic patients entered the study; 95 H. pylori infected (positive result of at least 4 of 5 diagnostic tests: Campylobacter-like organisms test (CLO test), histology, culture, stool antigens, serology) and 69 noninfected (negative results of 4 diagnostic tests: CLO test, histology, culture, stool antigens). Dental plaque was collected from natural teeth of the patients and incubated in microaerophilic conditions for 72 hours before immunoassay. RESULTS: Experimental findings included that optimal dental plaque weight to perform the examination was over 2 mg and that preliminary incubation increased significantly the number of positive results (p<0.002). It was also found that H. pylori antigens in the dental plaque were positive in 81.2% of infected and only 17.7% of non-infected subjects (p<0.001), while the reproducibility of results was 95%. CONCLUSIONS: The immunoassay for detection of H. pylori antigens in the stool may be used, after minor adaptations (specifically pre-incubation in microaerophilic conditions) for H. pylori antigen detection in dental plaque.