title: Functional genomics in Campylobacter coli identified a novel streptomycin resistance gene located in a hypervariable genomic region.
abstract: Numerous aminoglycoside resistance genes have been reported in Campylobacter spp. often resembling those from Gram-positive bacterial species and located in transferable genetic elements with other resistance genes. We discovered a new streptomycin (STR) resistance gene in Campylobactercoli showing 27-34 % amino acid identity to aminoglycoside 6-nucleotidyl-transferases described previously in Campylobacter. STR resistance was verified by gene expression and insertional inactivation. This ant-like gene differs from the previously described aminoglycoside resistance genes in Campylobacter spp. in several aspects. It does not appear to originate from Gram-positive bacteria and is located in a region corresponding to a previously described hypervariable region 14 of C. jejuni with no other known resistance genes detected in close proximity. Finally, it does not belong to a multiple drug resistance plasmid or transposon. This novel ant-like gene appears widely spread among C. coli as it is found in strains originating both from Europe and the United States and from several, apparently unrelated, hosts and environmental sources. The closest homologue (60 % amino acid identity) was found in certain C. jejuni and C. coli strains in a similar genomic location, but an association with STR resistance was not detected. Based on the findings presented here, we hypothesize that Campylobacter ant-like gene A has originated from a common ancestral proto-resistance element in Campylobacter spp., possibly encoding a protein with a different function. In conclusion, whole genome sequencing allowed us to fill in a knowledge gap concerning STR resistance in C. coli by revealing a novel STR resistance gene possibly inherent to Campylobacter.
authors.affiliation: Department of Food Hygiene and Environmental Health, Faculty of Veterinary Medicine, University of Helsinki, Finland.
authors.forename: Satu
authors.initials: S
authors.lastname: Olkkola
authors.affiliation: Department of Food Hygiene and Environmental Health, Faculty of Veterinary Medicine, University of Helsinki, Finland.
authors.forename: Alejandra
authors.initials: A
authors.lastname: Culebro
authors.affiliation: Department of Food Hygiene and Environmental Health, Faculty of Veterinary Medicine, University of Helsinki, Finland.
authors.forename: Pekka
authors.initials: P
authors.lastname: Juntunen
authors.affiliation: Department of Food Hygiene and Environmental Health, Faculty of Veterinary Medicine, University of Helsinki, Finland.
authors.forename: Marja-Liisa
authors.initials: ML
authors.lastname: Hänninen
authors.affiliation: Department of Food Hygiene and Environmental Health, Faculty of Veterinary Medicine, University of Helsinki, Finland.
authors.forename: Mirko
authors.initials: M
authors.lastname: Rossi
mesh_terms: D000595:Amino Acid Sequence / Q000235:genetics; D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001483:Base Sequence; D017000:Campylobacter coli / Q000187:drug effects* / Q000235:genetics* / Q000302:isolation & purification; D004269:DNA, Bacterial / Q000235:genetics; D024881:Drug Resistance, Bacterial / Q000235:genetics*; D014644:Genetic Variation / Q000235:genetics; D016680:Genome, Bacterial / Q000235:genetics; D008826:Microbial Sensitivity Tests; D017422:Sequence Analysis, DNA; D013307:Streptomycin / Q000494:pharmacology*; D013552:Swine / Q000382:microbiology
chemical_list: D000900:Anti-Bacterial Agents; D004269:DNA, Bacterial; D013307:Streptomycin