[A multicenter study of a new Helicobacter pylori selective medium. Columbia horse blood agar HP].

We conducted a study for the growth of and selectivity for the desired microorganisms using a newly developed selective culture medium for Helicobacter pylori, Columbia horse blood agar HP (CHBHP), at three different Japanese clinical laboratories, Hokkaido, Kanto and Kyusyu. When standard strains and clinical isolates of H. pylori were examined, the recovery of the organism on the CHBHP media was comparable to that of conventional selective and nonselective media. However, colonies were obviously larger on the CHBHP media. These media yielded the highest H. pylori positive rate for clinical specimens at all the three laboratories. The detection rate of the CHBHP media in H. pylori-positive specimens was higher than that of media commonly used at the three laboratories (98.1% to 100% vs. 88.0% to 96.2%). The CHBHP media also achieved a higher detection rate for specimens from H. pylori-infected animals. CHBHP media have an excellent growth supporting ability and selectivity originating from Columbia agar base and do not require the combined use of non-selective media for the growth and isolation of the organism, resulting in lower cost. Thus, they are useful media for the selective culture and isolation of H. pylori from clinical and animal specimens.