Nucleic acids in the classification of campylobacters

Abstract

The importance of campylobacters in human disease has stimulated improvements in the methods for identification of strains from hospitals and the environment, Reliable and accurate identification depends on a sound classification for which nucleic acid analyses provide fundamental information about species relationships. Studies on the genusCampylobacter show that the genome DNA of species have base compositions of 29 to 38 mol % G + C and molecular weights of 1.54× 10⁹ to 2.31×10⁹.Campylobacter fetus, the type species, has a mean G + C content of 35.7 mol % whereas those of the thermophilic speciesCampylobacter jejuni, Campylobacter coli and the NARTC group (Campylobacter laridis) are between 31.5 and 32.6 mol %. DNA-DNA hybridizations, which are useful in clarifying relationships at the species level, show clear differences between mostCampylobacter taxa. Distinct DNA sequence relatedness differences confirmedCampylobacter jejuni, Campylobacter coli and the NARTC group were separate species. The correlations between nucleic acid data and conventional biochemical test results, serology and fatty acid profiles are discussed. Further work is needed on the nucleic acids ofCampylobacter sputorum and the various allied campylobacters.