Prevalence and Molecular Characteristics of Extended-Spectrum and AmpC β-Lactamase Producing Escherichia coli in Grazing Beef Cattle

Shinyoung Lee; Lin Teng; Nicolas DiLorenzo; Thomas A Weppelmann; Kwangcheol Casey Jeong

doi:10.3389/fmicb.2019.03076

Prevalence and Molecular Characteristics of Extended-Spectrum and AmpC β-Lactamase Producing Escherichia coli in Grazing Beef Cattle

Front Microbiol. 2020 Jan 9:10:3076. doi: 10.3389/fmicb.2019.03076. eCollection 2019.

Authors

Shinyoung Lee^{1

2}, Lin Teng^{1

2}, Nicolas DiLorenzo³, Thomas A Weppelmann^{1

4}, Kwangcheol Casey Jeong^{1

2}

Affiliations

¹ Department of Animal Sciences, Emerging Pathogens Institute, University of Florida, Gainesville, FL, United States.
² Department of Animal Sciences, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, FL, United States.
³ North Florida Research and Education Center, Institute of Food and Agricultural Sciences, University of Florida, Marianna, FL, United States.
⁴ Herbert Wertheim College of Medicine, Florida International University, Miami, FL, United States.

Abstract

The emergence of extended-spectrum β-lactamase (ESBL) and AmpC β-lactamase producing Escherichia coli represent a contemporary public health threat. ESBL and AmpC β-lactamase genes translocate between chromosomes and plasmids, facilitating rapid spread throughout the environment. In this study, ESBL/AmpC producing bacteria were isolated from beef cattle farms with seldom antibiotic use. Eleven farms out of 17 tested, had ESBL/AmpC producing E. coli in animals, soil, and forage samples. Fifty-nine CTX-M or CMY-2 positive E. coli isolates were further characterized with whole-genome sequencing. The isolates commonly carried CMY-2, TEM, or CTX-M genes, and over half encoded both CTX-M and TEM genes. Using comparative genomics, antimicrobial resistance genes from 12 classes of antimicrobial were identified and confirmed by antibiotic susceptibility test, revealing multidrug resistance against multiple classes of antibiotics. Virulence factors related to adherence, invasion, iron uptake, and bacterial secretion systems were shared by all isolates; some of which were identified as enteropathogenic E. coli. Phylogenetic analyses revealed a pattern of close genetic relatedness, suggesting that ESBL/AmpC producing E. coli were transmitted among farms as well as independent evolution within farms. Our results indicate that ESBL and AmpC β-lactamases prevail in food animal production system regardless antibiotic use and have the characteristics for zoonotic transmission.

Keywords: AmpC; E. coli; ESBL; antibiotic resistance; grazing beef cattle.