Abstract
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. 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. 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. 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.
Highlights
The contamination of water environments by extended-spectrum β-lactamases-producing thermotolerant coliforms (ESBL-TC) has aroused public concern
Once entering into water bodies, ESBL-TC strains could contribute to the dissemination of antibiotic resistance genes within bacterial community via mobile genetic elements (MGE) [11]
A total of 981 TC were isolated from the Huangqian Reservoir, and 126 (126/981, 12.8%) ESBL-TC isolates were confirmed by the double disk diffusion method
Summary
The contamination of water environments by extended-spectrum β-lactamases-producing thermotolerant coliforms (ESBL-TC) has aroused public concern. 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. 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. It is believed that drug resistant bacteria from humans and animals, discharged into water bodies, could result in the spread of resistance genes within the bacterial community [37]. The persistence of antibiotic-resistant intestinal bacteria in water environments, extended-spectrum β-lactamase (ESBL)-producing bacteria, could elicit an important public health risk [8,9]. The integron system can import different combinations of antibiotic resistance genes, leading to the appearance of multi-drug resistant (MDR) bacteria [13,14]
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