Identification of thermophilic Campylobacter spp. by phenotypic and molecular methods

Aims: The differences between phenotyping and genotyping (polymerase chain reaction- restriction fragment length polymorphism) of Campylobacter jejuni , Campylobacter coli, Campylobacter lari and Campylobacter upsaliensis were assessed. Methods and Results: A total of 51, 63 and 88 strains from dogs, pigs and h umans, respectively, were examined. The strains were first typed by biochem ical methods, then by PCR-RFLP using AluI and Tsp509I. None of the strains were typed as Camp. lari by the PCR-RFLP. The biggest differences were foun d in the identification of Camp. jejuni and Camp. coli. The main discrepanc ies were caused with the hippurate hydrolysis test and sensitivity to cepha lothin and nalidixic acid. Strains which were identified biochemically as C amp. coli and by digestion with AluI as Camp. jejuni (eight strains) were t ested for the presence of the hippuricase gene. Conclusion: The PCR typing results showed the presence of the hippuricase g ene as unique to Camp. jejuni. Significance and Impact of the Study: A reliable identification of Campylob acter spp. should be supplemented with a molecular method.