Antimicrobial resistance and integrons of ESBL-producing thermotolerant coliforms from a water reservoir in Tai’an, China

Abstract

Introduction: The contamination of water environments by extended-spectrum β-lactamases-producing thermotolerant coliforms (ESBL-TC) has aroused public concern. However, little epidemiological data on ESBL-TC isolates from water reservoirs is available in China. Methodology: This study was designed to investigate antibiotic resistance, bla gene types, and the presence of integrons (class 1, 2, and 3) and gene cassettes in ESBL-TC isolated from the Huangqian Reservoir of Tai’an, China. Results: A total of 96 non-duplicate ESBL-TC were obtained in this study and the ESBL genes included blaCTX-M-14 (n = 47), blaCTX-M-15 (n = 27), blaCTX-M-55 (n = 18), blaSHV-12 (n = 4), blaCTX-M-3 (n = 3), and blaCTX-M-123 (n = 1). Eighty-three of the ninety-six ESBL-TC contained class 1 integrons (86.5%), and 2 isolates harbored class 2 integrons. The sizes of gene cassette regions within integrons were ranged from 0.2 kb to 3.2 kb. Conclusions: The findings of this study indicated the widespread presence of ESBL-TC strains in the Huangqian Reservoir and spotlighted the potential role of water bodies as reservoirs for antibiotic resistant genes.