Prevalence and Characterization of Quinolone-Resistance Determinants in Escherichia coli Isolated from Food-Producing Animals and Animal-Derived Food in the Philippines
Lawrence P. Belotindos, Marvin A. Villanueva, Joel Miguel, Precious Bwalya, Tetsuya Harada, Ryuji Kawahara, Chie Nakajima, Claro N. Mingala, Yasuhiko Suzuki
Abstract
Antimicrobial resistance to quinolones, which constitutes a threat to public health, has been increasing worldwide. In this study, we investigated the prevalence of quinolone-resistant determinants in Escherichia coli not susceptible to quinolones and isolated from food-producing animals and food derived from them, in the Philippines. A total of 791 E. coli strains were isolated in 56.4% of 601 beef, chicken, pork, egg, and milk samples, as well as environmental, cloacal, and rectal swab-collected samples from supermarkets, open markets, abattoirs, and poultry, swine, and buffalo farms. Using the disc diffusion method, it was determined that 78.6% and 55.4% of the isolates were resistant to at least one antimicrobial and multiple drugs, respectively. In 141 isolates not susceptible to quinolones, 115 (81.6%) harbored quinolone-resistant determinants and had mutations predominantly in the quinolone-resistance determining regions (QRDRs) of gyrA and parC. Plasmid-mediated, quinolone resistance (PMQR) and Qnr family (qnrA1, qnrB4, and qnrS1) genes were detected in all isolates. Forty-eight sequence types were identified in isolates harboring mutations in QRDR and/or PMQR genes by multilocus sequence typing analysis. Moreover, 26 isolates harboring mutations in QRDR and/or PMQR genes belonged mostly to phylogroup B1 and Enteroaggregative E. coli. In conclusion, a high prevalence of E. coli was found in food-producing animals and products derived from them, which could potentially spread high-risk clones harboring quinolone-resistance determinants.