Distribution of antimicrobial resistance genes and class 1 integrons in Escherichia coli from Canadian beef cattle.

摘要

This study examined the distribution of antimicrobial resistance (AMR) genes and characterized class 1 integrons in Escherichia coli from Canadian beef cattle. Escherichia coli isolated from beef cattle at abattoirs were screened for the presence of genes conferring resistance to aminoglycosides, beta-lactams, fluoroquinolones, phenicols, sulfonamides, tetracycline, and trimethoprim. The distribution of AMR genes and observed statistical associations between genes were similar to previous studies. A novel association between the floR and blaCMY-2 genes caused by clustering of these two mobile resistance genes on a single plasmid was identified. Escherichia coli isolated from beef cattle at abattoirs and feedlots were screened for the presence of the intI1 gene of class 1 integrons. All the identified class 1 integrons were characterized to identify which gene cassettes and variants they possessed. A variety of gene cassettes and gene cassette combinations were identified in E. coli from both abattoirs and feedlots, some of them new for E. coli and for bacteria from cattle.