ABSTRACT
BACKGROUND: The selective media for culture of Helicobacter pylori(H. pylori) are Egg yolk emulsion medium, modified Thayer-Martin medium and Skirrow's medium. The non-selective media for culture of H. pylori are brucella agar, trypticase soy agar, and brain heart infusion agar. The selective media are more expensive and difficult to prepare than non-selective media, whereas non-selective media are difficult to isolate H. pylori due to contamination of upper respiratory tract bacteria. The objects of this study are to reduce upper respiratory contaminants by use of HCl-KCl buffer (H-K buffer) for primary isolation, and to compare with culture, CLO test, histologic examination and H. pylori IgG antibodies. METHODS: Seventy one patients underwent upper gastrointestinal endoscopy with biopsy. For 32 patients, two biopsies were taken from antrum: One for direct inoculation into blood agar plate, the other for pretreatment of H-K buffer. For fifty six patients, we performed culture, CLO test, histology, and H. pylori IgG. RESULTS: 1) Among the 32 patients, H. pylori were isolated in 25 patients (23 patients for direct inoculation and 25 patients for H-K pretreatment). Twelve cases among H-K buffer treatment group did not show contamination, whereas only two among direct inoculation group showed no contamination. The average number of contaminating colony forming unit (CFU) of direct inoculation and H-K buffer treatment were 77 and 9, respectively. 2) The positive rates of culture and CLO test, histology, and H. pylori IgG for H. pylori infection were 71.4%, 67.9%, 75.0%, and 57.1%, respective