title: Antibiotic resistance due to an unusual ColE1-type replicon plasmid in Aeromonas salmonicida.
abstract: Aeromonas salmonicida subsp. salmonicida is a fish pathogen known to have a rich plasmidome. In the present study, we discovered an isolate of this bacterium bearing an additional unidentified small plasmid. After having sequenced the DNA of that isolate by next-generation sequencing, it appeared that the new small plasmid is a ColE1-type replicon plasmid, named here pAsa7. This plasmid bears a functional chloramphenicol-acetyltransferase-encoding gene (cat-pAsa7) previously unknown in A. salmonicida and responsible for resistance to chloramphenicol. A comparison of pAsa7 with pAsa2, the only known ColE1-type replicon plasmid usually found in A. salmonicida subsp. salmonicida, revealed that even if both plasmids share a high structural similarity, it is still unclear if pAsa7 is a derivative of pAsa2 since they showed several mutations at the nucleotide level. Transcriptomic analysis revealed that the cat-pAsa4 gene, another chloramphenicol-acetyltransferase-encoding gene, found on the large plasmid pAsa4, was significantly more transcribed than cat-pAsa7. This was correlated with a higher chloramphenicol resistance for isolates bearing pAsa4 compared with the one having pAsa7. Finally, a phylogenetic analysis showed that both CAT-pAsa4 and CAT-pAsa7 proteins were in different clusters. The clustering was supported by the identity of residues involved in the catalytic site. In addition, to give a better understanding of the large drug-resistance panel of A. salmonicida, this study reinforces the hypothesis that A. salmonicida subsp. salmonicida is a considerable reservoir for mobile genetic elements such as plasmids.
authors.affiliation: Centre de recherche de l'Institut universitaire de cardiologie et de pneumologie de Québec (Hôpital Laval), 2725 Chemin Sainte-Foy, Quebec City, QC, Canada, G1V 4G5.|Institut de biologie intégrative et des systèmes, Pavillon Charles-Eugène-Marchand, Université Laval, 1030 avenue de la Médecine, Quebec City, QC, Canada, G1V 0A6.|Département de biochimie, de microbiologie et de bio-informatique, Faculté des sciences et de génie, Université Laval, 1045 avenue de la Médecine, Quebec City, QC, Canada G1V 0A6.
authors.forename: Antony T
authors.initials: AT
authors.lastname: Vincent
authors.affiliation: Institut de biologie intégrative et des systèmes, Pavillon Charles-Eugène-Marchand, Université Laval, 1030 avenue de la Médecine, Quebec City, QC, Canada, G1V 0A6.|Centre de recherche de l'Institut universitaire de cardiologie et de pneumologie de Québec (Hôpital Laval), 2725 Chemin Sainte-Foy, Quebec City, QC, Canada, G1V 4G5.|Département de biochimie, de microbiologie et de bio-informatique, Faculté des sciences et de génie, Université Laval, 1045 avenue de la Médecine, Quebec City, QC, Canada G1V 0A6.
authors.forename: Jean-Guillaume
authors.initials: JG
authors.lastname: Emond-Rheault
authors.affiliation: Institut de biologie intégrative et des systèmes, Pavillon Charles-Eugène-Marchand, Université Laval, 1030 avenue de la Médecine, Quebec City, QC, Canada, G1V 0A6.|Département de Chimie, Université Laval, Québec, Canada.
authors.forename: Xavier
authors.initials: X
authors.lastname: Barbeau
authors.affiliation: Institut de biologie intégrative et des systèmes, Pavillon Charles-Eugène-Marchand, Université Laval, 1030 avenue de la Médecine, Quebec City, QC, Canada, G1V 0A6.|Centre de recherche de l'Institut universitaire de cardiologie et de pneumologie de Québec (Hôpital Laval), 2725 Chemin Sainte-Foy, Quebec City, QC, Canada, G1V 4G5.|Département de biochimie, de microbiologie et de bio-informatique, Faculté des sciences et de génie, Université Laval, 1045 avenue de la Médecine, Quebec City, QC, Canada G1V 0A6.
authors.forename: Sabrina A
authors.initials: SA
authors.lastname: Attéré
authors.affiliation: Département de biochimie, de microbiologie et de bio-informatique, Faculté des sciences et de génie, Université Laval, 1045 avenue de la Médecine, Quebec City, QC, Canada G1V 0A6.|Groupe de Recherche en Écologie Buccale (GREB), Faculté de médecine dentaire, Université Laval, Quebec City, QC, Canada, G1V 0A6.
authors.forename: Michel
authors.initials: M
authors.lastname: Frenette
authors.affiliation: Institut de biologie intégrative et des systèmes, Pavillon Charles-Eugène-Marchand, Université Laval, 1030 avenue de la Médecine, Quebec City, QC, Canada, G1V 0A6.|Département de biochimie, de microbiologie et de bio-informatique, Faculté des sciences et de génie, Université Laval, 1045 avenue de la Médecine, Quebec City, QC, Canada G1V 0A6.
authors.forename: Patrick
authors.initials: P
authors.lastname: Lagüe
authors.affiliation: Institut de biologie intégrative et des systèmes, Pavillon Charles-Eugène-Marchand, Université Laval, 1030 avenue de la Médecine, Quebec City, QC, Canada, G1V 0A6.|Centre de recherche de l'Institut universitaire de cardiologie et de pneumologie de Québec (Hôpital Laval), 2725 Chemin Sainte-Foy, Quebec City, QC, Canada, G1V 4G5.|Département de biochimie, de microbiologie et de bio-informatique, Faculté des sciences et de génie, Université Laval, 1045 avenue de la Médecine, Quebec City, QC, Canada G1V 0A6.
authors.forename: Steve J
authors.initials: SJ
authors.lastname: Charette
mesh_terms: D048409:Aeromonas salmonicida / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification; D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics*; D001483:Base Sequence; D002701:Chloramphenicol / Q000494:pharmacology; D015500:Chloramphenicol O-Acetyltransferase / Q000235:genetics*; D024881:Drug Resistance, Bacterial / Q000235:genetics*; D005399:Fishes / Q000382:microbiology; D059014:High-Throughput Nucleotide Sequencing; D008826:Microbial Sensitivity Tests; D010802:Phylogeny; D010957:Plasmids / Q000235:genetics*; D012093:Replicon / Q000235:genetics; D017422:Sequence Analysis, DNA
chemical_list: D001426:Bacterial Proteins; C042833:ROM protein, Bacteria; D002701:Chloramphenicol; D015500:Chloramphenicol O-Acetyltransferase