Chromosomal tet(O)-harboring regions in Campylobacter coli isolates from turkeys and swine

Abstract

In turkey-derived Campylobacter coli isolates of a unique lineage (cluster II), the tetracycline resistance determinant tet(O) was chromosomal and was part of a gene cassette (transposon) interrupting a Campylobacter jejuni-associated putative citrate transporter gene. In contrast, the swine-derived C. coli strain 6461 harbored a chromosomal tet(O) in a different genomic location.

Fig 1

Organization of the tet(O)-harboring region in C. coli 6067 and C. jejuni IA3902 and genomically equivalent regions in other Campylobacter genomes. Arrow orientations indicate the putative directions of transcription. ORFs flanking the tet(O) cassette and conserved (cons.) among the genomes are in black. ORFs composing the cassette are in gray, while the putative citrate transporter ORF harboring the tet(O) cassette is in white. ORFs unique to specific genomes are striped. P1, P2, P4, P5, P7, and P8 are primers, which are also listed in Table 2. hypoth., hypothetical.

Fig 2

Genomic organization of the tet(O)-harboring-region in C. coli 6461 and homologous regions in other Campylobacter genomes. Arrow orientations indicate putative directions of transcription. ORFs flanking the tet(O) cassette and conserved among the genomes are in black. C. coli-specific ORFs in the flanking regions are in gray. P2 to P8 are primers, which are also listed in Table 2.

Fig 3

Conservation of the genomic location of the tet(O) cassette among cluster II C. coli strains. The PCR employed primers derived from the tet(O) cassette of C. coli 6067. (A) PCR using primers for region downstream of tet(O) (P1 and P2); (B) PCR using primers for the region upstream of tet(O) (primers P3 and P4); (C) PCR using tet(O) primers (internal primers P7 and P8). Lane 1, molecular weight markers (exACTGene cloning DNA ladder; Fisher Scientific International, Inc.); lanes 2 to 10, cluster II C. coli strains 6100, 6077, 6690, 6890, 6979, 7725, 8023, 8901, and 6252, respectively; lane 11, negative control (no DNA).