[Modified selective medium for isolation of Helicobacter pylori]

Abstract

To improve the detection rate of Helicobacter pylori, many kinds of media were tried and other antibiotics were incorporated according to the antimicrobial susceptibility patterns of clinical isolates in our hospital. We found that brain heart infusion agar supplemented with 1% IsoVitaleX and 5% sheep blood, containing nalidixic acid 10 micrograms/ml, vancomycin 6 micrograms/ml, amphotericin B 2 micrograms/ml and polymixin B 16 micrograms/ml (BNVP) or colistin 5 micrograms/ml (BNVC) inhibited the growth of contaminants without significant influence on the growth of H. pylori. However, colonies of primary isolates of H. pylori on BNVP media were larger than those on BNVC media, and easier to detect, Both BNVP and BNVC media yielded the same isolation rate. The organism was isolated from 67 of 91 endoscopic biopsy specimens (73.6%) obtained from the area of peptic ulcers, and from 37 of 125 specimens obtained from the area without lesion. The data were much superior to those in the early day, when the organism was only isolated from 6 of the 27 specimens (22%) obtained from patients with peptic ulcer disease. Because the contaminants and their antimicrobial susceptibility patterns may be varied in different hospitals, it is mandatory to modify selective media suitable for recovering H. pylori.