Molecular Epidemiology of Antibiotic-Resistant <i>Escherichia coli</i> from Farm-to-Fork in Intensive Poultry Production in KwaZulu-Natal, South Africa

• Main Authors: Katherine S. McIver (Author), Daniel Gyamfi Amoako (Author), Akebe Luther King Abia (Author), Linda A. Bester (Author), Hafizah Y. Chenia (Author), Sabiha Y. Essack (Author)
• Format: Book
• Published: MDPI AG, 2020-11-01T00:00:00Z.
• Subjects: article
• Online Access: Connect to this object online.
• Notes: 10.3390/antibiotics9120850; 2079-6382
• Keywords: antibiotic resistance; antibiotic resistance genes; <i>Escherichia coli</i>; intensive poultry production; farm-to-fork continuum; South Africa; Therapeutics. Pharmacology; RM1-950
• Source: Antibiotics, Vol 9, Iss 12, p 850 (2020)

The increased use of antibiotics in food animals has resulted in the selection of drug-resistant bacteria across the farm-to-fork continuum. This study aimed to investigate the molecular epidemiology of antibiotic-resistant <i>Escherichia coli</i> from intensively produced poultry in the uMgungundlovu District, KwaZulu-Natal, South Africa. Samples were collected weekly between August and September 2017 from hatching to final retail products. <i>E. coli</i> was isolated on eosin methylene blue agar, identified biochemically, and confirmed using polymerase chain reaction (PCR). Susceptibility to 19 antibiotics was ascertained by the Kirby-Bauer disc diffusion method. PCR was used to test for resistance genes. The clonal similarity was investigated using enterobacterial repetitive intergenic consensus polymerase chain reaction (ERIC-PCR). In total, 266 <i>E. coli</i> isolates were obtained from all the samples, with 67.3% being non-susceptible to at least one antibiotic tested and 6.7% multidrug resistant. The highest non-susceptibility was to ampicillin (48.1%) and the lowest non-susceptibility to ceftriaxone and azithromycin (0.8%). Significant non-susceptibility was observed to tetracycline (27.4%), nalidixic acid (20.3%), trimethoprim-sulfamethoxazole (13.9%), and chloramphenicol (11.7%) which have homologues used in the poultry industry. The most frequently observed resistance genes were <i>bla_CTX-M</i> (100%), <i>sul1</i> (80%), <i>tetA</i> (77%), and <i>tetB</i> (71%). ERIC-PCR grouped isolates into 27 clusters suggesting the spread of diverse clones across the farm-to-fork continuum. This reiterates the role of intensive poultry farming as a reservoir and a potential vehicle for the transmission of antibiotic resistance, with potentially severe public health implications, thus, requiring prompt and careful mitigation measures to protect human and environmental health.