Identification of a gene encoding a methyl-accepting chemotaxis-like protein from Campylobacter coli and its use in a molecular typing scheme for campylobacters

Using PCR amplification with degenerate primers, a gene ( tlpA ) from Campylobacter coli encoding a putative 63·0 kDa polypeptide which exhibited significant identity with bacterial methyl-accepting chemotaxis proteins (MCPs) was identified. A mutant containing an inactivated copy of the tlpA gene showed a wild-type chemotactic response to all of the chemo-attractants tested. A DNA probe based on the Highly Conserved Domain (HCD) of TlpA revealed the presence of multiple copies of genes encoding MCP-like proteins in both Camp. coli and Camp. jejuni. The arrangement of restriction sites within, and proximal to, genes with homology to the HCD probe varied among strains, resulting in a high degree of polymorphism. It is demonstrated here that a DNA probe comprising the HCD region of MCP-like proteins can be used, in Southern hybridization-based assays, to provide novel information which allows the discrimination of individual strains of Camp. coli and Camp. jejuni.