Description of Campylobacter laridis, a new species comprising the nalidixic acid resistant thermophilic Campylobacter (NARTC) group

Abstract

Ten strains of the nalidixic acid-resistant thermophilic Campylobacter (NARTC) group, of which 2 were isolated from human feces, were compared with 12 reference strains representing various species of Campylobacter. The NARTC strains were a homogeneous group with respect to their cell morphology and 28 physiological and biochemical characters. All were microaerophilic, motile (amphitrichate), gram-negative, curved, S-shaped or helical rods, and representative strains had mean DNA base compositions of 31 to 32 mol % G+C. Distinctive features of the 10 strains were resistance to nalidixic acid and anaerobic growth in the presence of trimethylamine N-oxide hydrochloride (TMAO). The latter feature may account for the common occurrence of NARTC strains in the fecal contents of seagulls. DNA-DNA hybridizations indicated high (≥76%) base sequence relatedness within the group and low (≤15%) relatedness to other species of Campylobacter. The 10 strains were classified in the genus Campylobacter but they could not be assigned to any previously defined species. Therefore, a new species, with the name Campylobacter laridis, is proposed for these 10 strains; the type strain is NCTC 11352. © 1983 Springer-Verlag.