Specimens were processed within less than 1 h. Each biopsy specimen from each patient was separately minced within their transport medium in a tissue grinder (mortar) using a sterile pestle and rapidly inoculated onto selective Columbia Blood Agar (CBA; Oxoid, England) plates supplemented with 5% defibrinated sheep blood, including, trimethoprim (5 mg/l), cefsulodin (5 mg/l), vancomycin (10 mg/l), and amphotericin B (5 mg/l). Plates were incubated at 37 °C in an anaerobic jar for 3–10 days under microaerophilic conditions (5% O2, 10% CO2 and 85% N2) by using Campygen kits (Oxoid, Basingstoke, UK). Small fragments from each grinded biopsy specimen were separately placed into Christensen's Urea Broth (CUB) for a rapid urease test.
Bacterial morphology was examined by Gram staining to verify the presence of Gram-negative spiral rod-shaped bacteria and typical colony morphology (small round colonies) as shown in Supplemental data;Fig. S1 . Bacterial isolates recovered from microaerophilic conditions were confirmed phenotypically as H. pylori on the basis of positive reactions for urease, catalase and oxidase tests.39 (link) In this study 20 out of 45 cultivated gastric biopsies were positive for H. pylori and were designated as HP-1 to HP-20.
Bacterial morphology was examined by Gram staining to verify the presence of Gram-negative spiral rod-shaped bacteria and typical colony morphology (small round colonies) as shown in Supplemental data;