Comparison of Selective Media for Culture of Helicobacter pylori

Paik, In Ki; Kim, Yong Soon; Shin, Won Chang; Lee, Jin Ho

Abstract

BACKGROUNDS: Culture of Helicobacter pylori (H. pylori) from gastric biopsy specimens is a standard method with high specificity among H. pylori diagnostic tools and is also essential for antibiotic susceptibility test. The authors compared 5 selective media for H. pylori culture and tested fresh human serum instead of fresh animal blood as a media composite.
METHODS
Gastric biopsy specimens from endoscopic examination were obtained from 50 patients (gastric ulcer:33, duodenal ulcer:12, stomach cancer:5) and they were finely minced with a tissue grinder. Specimens were inoculated onto 5 media (1. Columbia agar with 5% sheep blood, 2. Columbia agar with 10% human serum, 3. Thayer-Martin agar with 5% sheep blood, 4. T-M agar with 10% human serum, 5. T-M agar with 10% hemoglobin) and cultured for 3~7 days under microaerophilic condition. Gram stain, oxidase, catalase, and urease tests, were undertaken on typical colonies for diagnosis of H. pylori. Contamination by other organisms, number and size of H. pylori colonies were compared for each media.
RESULTS
Positive culture rate of H. pylori was not significantly different among 4 media except TM agar with 10% hemoglobin. However T-M agar with 10% fresh human serum was considered as the best composition for culture of H. pylori because it had the least contaminating organisms and produced the largest colony sizes.
CONCLUSIONS
These findings suggest that T-M agar with 10% fresh human serum can replace columbia agar with 5% sheep blood which has been commonly used for culture of H. pylori from gastric biopsy specimens. Fresh human serum, which is easily obtained in the clinical laboratory, can replace animal bloods in making media for H. pylori.