Genetic relationships among reptilian and mammalian Campylobacter fetus strains determined by multilocus sequence typing

Abstract

Reptile Campylobacter fetus isolates and closely related strains causing human disease were characterized by multilocus sequence typing. They shared approximately 90% nucleotide sequence identity with classical mammalian C. fetus, and there was evidence of recombination among members of these two groups. The reptile group represents a possible separate genomospecies capable of infecting humans.

FIG. 1.

Consensus tree (Newick tree) constructed using ClonalFrame (2) and viewed using MEGA (9) to show the two distinct groups formed by classical mammalian and reptile C. fetus. sap types associated with the STs are indicated. Input sequences comprised the concatenated sequences of the seven MLST loci.

FIG. 2.

Nucleotide sequence alignment of concatenated STs showing the variable sites only. Dots indicate identity to ST-1. This illustrates the relationship between classical mammalian C. fetus, represented by ST-1, and reptile C. fetus, represented by ST-27. The confirmed recombinant reptile C. fetus strain, ST-16, has a high level of sequence identity with classical mammalian C. fetus in the pgm locus, shown by black shading. The possible recombinant ST-26 reptile C. fetus strain has a sequence divergent from those of reptile C. fetus ST-27 and ST-16 in the aspA locus, indicated by black shading.