Distribution of the pco Gene Cluster and Associated Genetic Determinants among Swine Escherichia coli from a Controlled Feeding Trial

Genes

HarveyMorgan Scott¹  Gabhan Chalmers²  MikeD. Tokach³  KeriN. Norman⁴  KellyM. Rozas⁴  RaghavendraG. Amachawadi⁵  Patrick Boerlin⁵  TiruvoorG. Nagaraja⁵ 

[1] Department of Clinical Sciences, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506, USA;Department of Pathobiology, Ontario Veterinary College, University of Guelph, 50 Stone Rd. E., Guelph, ON N1G 2W1, Canada;;Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&;Department of Veterinary Pathobiology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX 77843, USA;

关键词: copper;    resistance;    swine;    Escherichia coli;   

DOI  :  10.3390/genes9100504

来源: DOAJ

【 摘 要 】

Copper is used as an alternative to antibiotics for growth promotion and disease prevention. However, bacteria developed tolerance mechanisms for elevated copper concentrations, including those encoded by the pco operon in Gram-negative bacteria. Using cohorts of weaned piglets, this study showed that the supplementation of feed with copper concentrations as used in the field did not result in a significant short-term increase in the proportion of pco-positive fecal Escherichia coli. The pco and sil (silver resistance) operons were found concurrently in all screened isolates, and whole-genome sequencing showed that they were distributed among a diversity of unrelated E. coli strains. The presence of pco/sil in E. coli was not associated with elevated copper minimal inhibitory concentrations (MICs) under a variety of conditions. As found in previous studies, the pco/sil operons were part of a Tn7-like structure found both on the chromosome or on plasmids in the E. coli strains investigated. Transfer of a pco/sil IncHI2 plasmid from E. coli to Salmonella enterica resulted in elevated copper MICs in the latter. Escherichia coli may represent a reservoir of pco/sil genes transferable to other organisms such as S. enterica, for which it may represent an advantage in the presence of copper. This, in turn, has the potential for co-selection of resistance to antibiotics.

【 授权许可】

Unknown