Prevalence and Antimicrobial Susceptibility of Indicator Organisms Escherichia coli and Enterococcus spp. Isolated from U.S. Animal Food, 2005-2011

• Published in: Microorganisms (Basel) Vol. 8; no. 7; p. 1048
• Main Authors: Ge, Beilei, Domesle, Kelly J, Gaines, Stuart A, Lam, Claudia, Bodeis Jones, Sonya M, Yang, Qianru, Ayers, Sherry L, McDermott, Patrick F
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 15.07.2020; MDPI
• Subjects: Animal feed; animal food; Animals; Antimicrobial agents; Antimicrobial resistance; antimicrobial susceptibility; Ciprofloxacin; Deoxyribonucleic acid; DNA; Drug resistance; E coli; Enterococcus; Escherichia coli; Feeds; Food chains; Food production; Food products; Health aspects; Ingredients; Laboratories; Meat; Multidrug resistance; Organisms; pet food; Petfoods; Pets; Salmonella; Surveillance; Veterinary medicine; United States; United States > US; China; Enterococcus; animal feed; animal food; pet food; prevalence; Escherichia coli; antimicrobial susceptibility; resistance
• ISSN: 2076-2607; 2076-2607
• DOI: 10.3390/microorganisms8071048

The role animal food plays in the introduction of antimicrobial-resistant bacteria into the human food chain is not well understood. We conducted an analysis of 1025 samples (647 pet food and 378 animal feed) collected across the United States during 2005-2011 for two indicator organisms ( and spp.). The overall prevalence ranged from 12.5% for to 45.2% for spp., and 11.2% of samples harbored both organisms. Regardless of bacterial genus, animal feed had significantly higher prevalence than pet food ( < 0.001). A general downward trend in prevalence was observed from 2005 to 2009 followed by an upward trend thereafter. Among isolates ( = 241), resistance was highest to tetracycline (11.2%) and below 5% for fourteen other antimicrobials. Among spp. isolates ( = 1074), (95.1%) was the predominant species. Resistance was most common to tetracycline (30.1%) and ciprofloxacin (10.7%), but below 10% for thirteen other antimicrobials. Multidrug-resistant organisms were observed among both and spp. isolates at 3.3%. Compared to National Antimicrobial Resistance Monitoring System (NARMS) 2011 retail meat and animal data, the overall resistance for both organisms was much lower in animal food. These findings help establish a historic baseline for the prevalence and antimicrobial resistance among U.S. animal food products and future efforts may be needed to monitor changes over time.