2024 journal article
Widespread prevalence of plasmid-mediated <i>bla</i><sub>CTX-M</sub> type extended-spectrum beta-lactamase <i>Escherichia coli</i> in backyard broiler production systems in the United States
PLOS ONE, 19(6).
journals.plos.org (publisher PDF)
Source: Web Of Science
Added: June 17, 2024
Extended-spectrum beta-lactamase (ESBL) Escherichia coli ( E . coli ) is an emerging pathogen of high concern given its resistance to extended-spectrum cephalosporins. Broiler chicken, which is the number one consumed meat in the United States and worldwide, can be a reservoir of ESBL E . coli . Backyard poultry ownership is on the rise in the United States, yet there is little research investigating prevalence of ESBL E . coli in this setting. This study aims to identify the prevalence and antimicrobial resistance profiles (phenotypically and genotypically) of ESBL E . coli in some backyard and commercial broiler farms in the U.S. For this study ten backyard and ten commercial farms were visited at three time-points across flock production. Fecal (n = 10), litter/compost (n = 5), soil (n = 5), and swabs of feeders and waterers (n = 6) were collected at each visit and processed for E . coli . Assessment of ESBL phenotype was determined through using disk diffusion with 3 rd generation cephalosporins, cefotaxime and ceftazidime, and that with clavulanic acid. Broth microdilution and whole genome sequencing were used to investigate both phenotypic and genotypic resistance profiles, respectively. ESBL E . coli was more prevalent in backyard farms with 12.95% of samples testing positive whereas 0.77% of commercial farm samples were positive. All isolates contained a bla CTX-M gene, the dominant variant being bla CTX-M-1 , and its presence was entirely due to plasmids. Our study confirms concerns of growing resistance to fourth generation cephalosporin, cefepime, as roughly half (51.4%) of all isolates were found to be susceptible dose-dependent and few were resistant. Resistance to non-beta lactams, gentamicin and ciprofloxacin, was also detected in our samples. Our study identifies prevalence of bla CTX-M type ESBL E . coli in U.S. backyard broiler farms, emphasizing the need for interventions for food and production safety.