@article{chan_elhanafi_kathariou_2008, title={Genomic evidence for interspecies acquisition of chromosomal DNA from Campylobacter jejuni by Campylobacter coli strains of a turkey-associated clonal group (cluster II)}, volume={5}, ISSN={["1556-7125"]}, DOI={10.1089/fpd.2008.0113}, abstractNote={Previous multilocus sequence typing studies of Campylobacter coli from meat animals identified an unusual cluster of strains, primarily from turkeys, termed "cluster II" and characterized by the presence of the C. jejuni aspA103 allele. To characterize the extent of genomic input from C. jejuni in the aspA region of cluster II C. coli, we sequenced the 6.1 kb genomic region upstream of and including aspA from two turkey-derived cluster II strains (C. coli 6979 and C. coli 7474, of ST-1150 and ST-1161, respectively), as well as from a turkey-derived multidrug-resistant strain (C. coli 6818) representing a major sequence type (ST-1101) outside of cluster II. A gene encoding a putative CRP-family transcriptional regulator (CCO0137) was present in C. coli 6818 and the reference strain C. coli RM2228, whose genome has been sequenced, but not in either cluster II strain evaluated. This gene was also absent from C. jejuni NCTC 11168 and C. jejuni RM1221. Moreover, single nucleotide polymorphism (SNP) analysis revealed that in both cluster II strains, genes encoding subunit II of cytochrome d ubiquinol oxidase (cydB) and a putative aspartate racemase (Cj0085c) harbored numerous C. jejuni-specific SNPs. Interestingly, genes encoding subunit I of cytochrome d ubiquinol oxidase (cydA), uracil-DNA glycosylase (ung), and aspartate ammonia-lyase (aspA) harbored C. coli-specific SNPs in certain portions but C. jejuni-specific SNPs in others, suggesting that these were hybrid genes with C. jejuni-derived segments. Analysis of a ung mutant in C. coli 7474 indicated that the putative hybrid ung of this cluster II strain was functional. Our data suggest the occurrence of recombination events that resulted in genomic import of DNA from C. jejuni in the region between cydA and aspA in cluster II strains of C. coli.}, number={4}, journal={FOODBORNE PATHOGENS AND DISEASE}, author={Chan, Kamfai and Elhanafi, Driss and Kathariou, Sophia}, year={2008}, month={Aug}, pages={387–398} }
 @article{chan_miller_mandrell_kathariou_2007, title={The absence of intervening sequences in 23S rRNA genes of Campylobacter coli isolates from turkeys is a unique attribute of a cluster of related strains which also lack resistance to erythromycin}, volume={73}, ISSN={["1098-5336"]}, DOI={10.1128/AEM.01995-06}, abstractNote={ABSTRACT
          
            Certain
            Campylobacter
            strains harbor a transcribed intervening sequence (IVS) in their 23S rRNA genes. Following transcription, the IVS is excised, leading to fragmentation of the 23S rRNA. The origin and possible functions of the IVS are unknown. Furthermore, the distribution of IVS-harboring strains within
            Campylobacter
            populations is poorly understood. In this study, 104 strains of
            Campylobacter coli
            from turkeys, representing 27 different multilocus sequence typing-based sequence types (STs), were characterized in terms of IVS content and erythromycin susceptibility. Sixty-nine strains harbored IVSs in all three 23S rRNA genes, whereas the other 35 strains lacked IVSs from at least one of the genes. The STs of the latter strains belonged to an unusual cluster of
            C. coli
            STs (cluster II), earlier found primarily in turkey strains and characterized by the presence of the
            C. jejuni aspA103
            allele. The majority (66/69) of strains harboring IVSs in all three 23S rRNA genes were resistant to erythromycin, whereas none of the 35 strains with at least one IVS-free 23S rRNA gene were resistant. Cluster II strains could be transformed to erythromycin resistance with genomic DNA from
            C. coli
            that harbored IVS and the A2075G transition in the 23S rRNA gene, associated with resistance to erythromycin in
            Campylobacter
            . Erythromycin-resistant transformants harbored both the A2075 transition and IVS. The findings suggest that the absence of IVS in
            C. coli
            from turkeys is characteristic of a unique clonal group of erythromycin-susceptible strains and that IVS can be acquired by these strains via natural transformation to erythromycin resistance.
          }, number={4}, journal={APPLIED AND ENVIRONMENTAL MICROBIOLOGY}, author={Chan, Kamfai and Miller, William G. and Mandrell, Robert E. and Kathariou, Sophia}, year={2007}, month={Feb}, pages={1208–1214} }