The test for hippurate hydrolysis is critical for separation of Campylobacterjejuni and C. coli strains. Glycine and benzoic acid are formed when hippurate is hydrolyzed by C. jejuni. The test used in most laboratories is one of several variations of the ninhydrin tube test described by Hwang and Ederer (M. Hwang and G. M. Ederer, J. Clin. Microbiol. 1:114-115, 1975) for detection of glycine. We evaluated three modifications of the Hwang and Ederer method and the gas-liquid chromatographic (GLC) method described by Kodaka et al. (H.

The availability of iron to potentially pathogenic bacterial strains is restricted by the iron-binding proteins of the host. In this study, we examined 40 strains of Campylobacter species grown under iron-limiting conditions. While the strains produced no detectable siderophores, all the isolates freely utilized exogenous siderophores produced by other organisms as iron carriers. These data suggest that the use of an exogenous siderophore (either purified or present in a coinfecting microorganism) may be important in developing a suitable laboratory model for campylobacteriosis.

During a 2-year period, 14 biochemically atypical Campylobacterfetus subsp. fetus-like strains were received by the Campylobacter Reference Laboratory at the Centers for Disease Control. Sources of the isolates were blood, nine strains; stools, two strains; amniotic fluid, one strain; and abscesses, two strains. Atypical phenotypic characteristics exhibited by one or more strains were growth at 42°C, 10 strains; no H2S by lead acetate paper, 3 strains; resistance to a 30-pg cephalothin disk, 2 strains; and nonmotility, 1 strain. By DNA-DNA hybridization, all 14 isolates and the type strain of C. fetus subsp. fetus (ATCC 27374) were 94 to 100% related in reassociation reactions at 50°C, with 0.0 to 0.5% divergence, and were 86 to 100% related in reassociation reactions at 65°C. Thus, all of these atypical strains were C. fetus subsp. fetus. MICs of 11 antimicrobial agents for these 14 strains were variable. All strains were susceptible to chloramphenicol, erythromycin, gentamicin, and tetracycline, and most were susceptible to ampicillin, clindamycin, and penicillin. Eleven strains were resistant to cephalothin (MIC-16 ,ug/ml), nine were resistant to rifampin (MIC >-8 ,ug/ml), and all were resistant to nalidixic acid (MIC > 32 ,ug/ml) and vancomycin (MIC > 32 ,ug/ml). One can expect to see biochemical variability in C. fetus subsp. fetus strains and to encounter such strains from a variety of human sources, the most important of which appears to be blood.

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