Phylogenetic Analysis and PCR-Restriction Fragment Length Polymorphism Identification of CampylobacterSpecies Based on Partial groELGene Sequences

ABSTRACTThe phylogeny of 12 Campylobacterspecies and reference strains of Arcobacter butzleriand Helicobacter pyloriwas studied based on partial 593-bp groELgene sequences. The topology of the phylogenetic neighbor-joining tree based on the groELgene was similar to that of the tree based on the 16S rRNA gene. However, groELwas found to provide a better resolution for Campylobacterspecies, with lower interspecies sequence similarities (range, 65 to 94%) compared with those for the 16S rRNA gene (range, 90 to 99%) and high intraspecies sequence similarities (range, 95 to 100%; average, 99%). A new universal reverse primer that amplifies a 517-bp fragment of the groELgene was developed and used for PCR-restriction fragment length polymorphism (PCR-RFLP) analysis of 68 strains representing 11 Campylobacterspecies as well as reference strains of A. butzleriiand H. pylori. Digestion with the AluI enzyme discriminated all Campylobacterspecies included in the study but showed more intraspecies diversity than digestion with the ApoI enzyme. A hippurate-negative variant of Campylobacter jejuniwith a high level of groELsequence similarity to both C. jejuni(96%) and C. coli(94%) gave a unique AluI profile and an ApoI profile identical to those of other C. jejunistrains. In conclusion, groELgene sequencing and PCR-RFLP analysis are recommended as valuable tools for the identification of Campylobacterspecies.