血液培養からの<I>Helicobacter cinaedi</I>及びその類縁菌の分離培養と簡便同定法に関する検討

Abstract

A spiral Gram-negative bacterium, Helicobacter cinaedi, has been isolated from clinical specimens of immunodeficient patients in Japan. We determined the isolation procedure and features using practical phenotypic tests for H. cinaedi isolated from blood culture. We applied 28 clinically isolated strains from 5 different metropolitan institutions, whose species was reconfirmed in technical support at another expert veterinary medicine institute in identifying H. cinaedi. We also used 6 strains of type and reference. Positive signals from aerobic bottles in automated blood culture systems, BACTEC, were observed 4-9 days after culture was started. A thin spread colony was found 3-4 days after the start of subcultures consisting of growth on 5% sheep blood agar plates with immediate incubation under wet and microaerophilic conditions at 35 degrees C. In phenotypic tests, all specimens of H. cinaedi were shown to be positive in nitrate reduction and to be negative in both indoxyl acetate hydrolysis and urease activity, underlining the usefulness of these 3 phenotypes. Tests of alkaline phosphatase hydrolysis, growth at different temperatures, and growth with 1% glycin provided additional information when referencing standard results of identification. We took speculative profiling data of H. cinaedi identification with a simple phenotypic kit, Api campy, indicating its usefulness in testing. These observations suggest combined methods of previously available tests (nitrate reduction, indoxyl acetate hydrolysis, and urease activity) with Api campy may be useful in differentiating H. cinaedi from H. cinaedi-like microorganisms when observing the characteristic thin spread colony within subcultures under microaerophilic conditions.