Molecular discrimination between Campylobacter jejuni, Campylobacter coli, Campylobacter lari and Campylobacter upsaliensis by polymerase chain reaction based on a novel putative GTPase gene.

Polymerase chain reaction (PCR) mediated DNA fingerprinting has resulted in the identification of a novel Campylobacter jejuni gene, encoding a GTPase protein. The gene, consisting of 383 amino acids contained semi-conserved GTP-binding sites (designated G-1 to G-4), that are characteristic for members of the GTPase protein superfamily. Remarkably, this gene from C. Jejuni appears to encode a member of a novel family of GTP-binding proteins, containing two separate putative GTP-binding domains, each comprising a series of semi-conserved GTP-binding motifs. Spacing between these motifs is highly conserved. Based on this novel gene, a general PCR strategy for the identification of C. jejuni, C. coli, C. lari and C. upsaliensis was developed. PCR primers were deduced from GTP-binding motifs G-1 and G-3 of the first GTP-binding domain. These GTP-binding sites flank a variable region of precisely 117 bp in the four Campylobacter spp. that allowed the development of species-specific probes. This PCR-hybridization assay offers a novel tool for rapid molecular detection and specific identification of the thermophilic Campylobacter spp.