Three supplementary diagnostic tests for Campylobacter species and related organisms.

We analyzed 307 recent clinical isolates and reference strains of Campylobacter spp., Helicobacter spp., and Arcobacter spp. for arylsulfatase and pyrazinamidase activities and susceptibility to polymyxin B. All isolates studied were identified by DNA dot hybridization prior to testing. Campylobacter concisus, C. sputorum, and Helicobacter fennelliae were positive for arylsulfatase. C. jejuni, C. coli, C. lari, C. upsaliensis, and C. concisus were positive for pyrazinamidase. Only Helicobacter spp. were resistant to polymyxin B. C. fetus subsp. fetus, C. hyointestinalis, C. mucosalis, and Arcobacter spp. were negative in all three tests. The tests were simple to perform and read, and with the exception of C. sputorum biovars, all isolates within a species gave consistently positive or negative results in all the assays. These three phenotypic tests may help refine current methods for phenotypic identification of Campylobacter spp. and related organisms in a reference laboratory setting.