Imported Retail Beef and Chicken Meat Products Serve as Reservoirs for Emerging Antibiotic-Resistant Pathotypes of Escherichia coli in Pristine Areas Free From Agricultural Activity.

Abstract

Increasing attention is being directed toward the role of retail meat in introducing pathogens and antibiotic-resistant bacteria into local food supplies. This study characterized the antibiotic resistance (AR) and virulence of E. coli isolates from chicken and beef (n = 109) imported for retail sale in Kasane, Botswana. In this relatively pristine environment, commercial beef and chicken production is absent, resulting in reliance on imports, creating concerns that multidrug-resistant (MDR) and pathogenic E. coli may be introduced through the food supply sourced from distant regions. E. coli was isolated from 54.7% of samples (63/109). Antibiotic susceptibility testing against a panel of 12 antibiotics revealed resistance to 11 antibiotics, with multiple combinations of resistance phenotypes identified. Higher levels of MDR were found in chicken isolates (45.5%) compared to beef (13.3%), with the highest resistance rates observed for tetracycline, trimethoprim/sulfamethoxazole, and doxycycline. Genomic analysis of eight MDR isolates revealed diverse sequence types, including diarrheagenic and extraintestinal-associated serotypes. The latter has critical implications in health systems where this clinical presentation may not be investigated with foodborne pathogen exposures. Plasmid-borne AR genes with conjugation-associated genes were detected in most isolates, suggesting that some AR genes may be horizontally transferable by plasmid conjugation. Several isolates clustered with human and chicken isolates from around the globe, highlighting the high potential for retail beef and chicken products to harbor MDR pathogenic E. coli, including emerging pathogens, and to introduce those microbes and associated AR attributes into new ecosystems.