Restriction fragment length polymorphism analysis shows that the hippuricase gene of Campylobacter jejuni is highly conserved.

A 1151-bp amplicon containing the hippuricase (hipO) gene was obtained from 118 strains of Campylobacter jejuni and double-digested with AluI and DdeI to give five different PCR-RFLP patterns. Most strains had the six-banded profile predicted from sequence data. Lack of polymorphisms within the hipO gene indicated it was highly conserved amongst strains of Camp.jejuni, and the RFLP analysis provided only low discrimination as an epidemiological typing method. Detection of hipO by PCR provided a useful test for confirmatory identification of Camp. jejuni.