A putative adhesin gene cloned from Campylobacter jejuni

Thirteen Campylobacter jejuni strains of human origin showed differing behaviours when analysed for their ability to bind the Caco-2 cell line in vitro, suggesting variations in genetic complements and/or regulation. We designed an oligonucleotide probe corresponding to a highly conserved part of adhesins from various Gram-negative bacteria. Among our laboratory collection, Southern hybridization has demonstrated that only a discrete number of strains harbour this sequence. The corresponding gene has been cloned from our prototype strain and sequence analysis has confirmed homology with Gram-negative bacterial adhesins. The ORF corresponded to 869 amino acids; we named this protein P95. Protein sequence similarity assessment demonstrated that this gene product belongs to the family of proteins including the filamentous haemagglutinin of Bordetella pertussis and the high-molecular-weight surface-exposed adhesins of Haemophilus influenzae. Comparison of adhesion and hybridization results emphasized the involvement of this gene in an essential pathogenic process of Campylobacter.