TY - JOUR
T1 - Comparative genomics and phylogeny of the IncI1 plasmids
T2 - A common plasmid type among porcine enterotoxigenic Escherichia coli
AU - Johnson, Timothy J.
AU - Shepard, Sara M.
AU - Rivet, Bernadette
AU - Danzeisen, Jessica L.
AU - Carattoli, Alessandra
N1 - Funding Information:
This project was funded by the Minnesota Pork Board and supported by the Italy–USA cooperation project – Italian Ministry of Health grant DRE 29/12/2010-0001090.
PY - 2011/9
Y1 - 2011/9
N2 - Increasing reports of multidrug resistance conferred by conjugative plasmids of Enterobacteriaceae necessitate a better understanding of their evolution. One such group is the narrow-host-range IncI1 plasmid type, known for their ability to carry genes encoding resistance to extended-spectrum beta lactamases. The focus of this study was to perform comparative sequencing of IncI1 plasmids from porcine enterotoxigenic Escherichia coli (ETEC), isolated irrespective of antimicrobial susceptibility phenotype. Five IncI1 plasmids of porcine ETEC origin and one IncI1 plasmid from a Salmonella enterica serovar Kentucky isolate from a healthy broiler chicken were sequenced and compared to existing IncI1 plasmid sequences in an effort to better understand the overall genetic composition of the IncI1 plasmid lineages. Overall, the sequenced porcine ETEC IncI1 plasmids were divergent from other sequenced IncI1 plasmids based upon multiple means of inferred phylogeny. High occurrences of IncI1 and IncA/C plasmid-associated genes and the bla TEM and bla CMY-2 beta lactamase genes were observed among porcine ETEC. However, the presence of bla TEM and bla CMY-2 did not strongly correlate with IncI1 plasmid possession, suggesting that these plasmids in porcine ETEC are not primarily associated with the carriage of such resistance genes. Overall, this work suggests a conservation of the IncI1 plasmid backbone among sequenced plasmids with a single locus for the acquisition of accessory genes, such as those associated with antimicrobial resistance. Furthermore, the high occurrence of IncI1 and IncA/C plasmids among clinical E. coli from commercial swine facilities is indicative of extensive horizontal gene transfer among porcine ETEC.
AB - Increasing reports of multidrug resistance conferred by conjugative plasmids of Enterobacteriaceae necessitate a better understanding of their evolution. One such group is the narrow-host-range IncI1 plasmid type, known for their ability to carry genes encoding resistance to extended-spectrum beta lactamases. The focus of this study was to perform comparative sequencing of IncI1 plasmids from porcine enterotoxigenic Escherichia coli (ETEC), isolated irrespective of antimicrobial susceptibility phenotype. Five IncI1 plasmids of porcine ETEC origin and one IncI1 plasmid from a Salmonella enterica serovar Kentucky isolate from a healthy broiler chicken were sequenced and compared to existing IncI1 plasmid sequences in an effort to better understand the overall genetic composition of the IncI1 plasmid lineages. Overall, the sequenced porcine ETEC IncI1 plasmids were divergent from other sequenced IncI1 plasmids based upon multiple means of inferred phylogeny. High occurrences of IncI1 and IncA/C plasmid-associated genes and the bla TEM and bla CMY-2 beta lactamase genes were observed among porcine ETEC. However, the presence of bla TEM and bla CMY-2 did not strongly correlate with IncI1 plasmid possession, suggesting that these plasmids in porcine ETEC are not primarily associated with the carriage of such resistance genes. Overall, this work suggests a conservation of the IncI1 plasmid backbone among sequenced plasmids with a single locus for the acquisition of accessory genes, such as those associated with antimicrobial resistance. Furthermore, the high occurrence of IncI1 and IncA/C plasmids among clinical E. coli from commercial swine facilities is indicative of extensive horizontal gene transfer among porcine ETEC.
KW - Escherichia coli
KW - Genomics
KW - IncI1
KW - Plasmid
KW - Porcine
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U2 - 10.1016/j.plasmid.2011.07.003
DO - 10.1016/j.plasmid.2011.07.003
M3 - Article
C2 - 21843549
AN - SCOPUS:81055156189
SN - 0147-619X
VL - 66
SP - 144
EP - 151
JO - Plasmid
JF - Plasmid
IS - 3
ER -