Abstract
Antimicrobial resistance (AMR) has become a major concern worldwide. To evaluate the AMR of Escherichia coli in aquaculture farms of Zhanjiang, China, a total of 90 samples from the water, soil, and sediment of three aquaculture farms (farms I, II, and III) in Zhanjiang were collected, and 90 strains of E. coli were isolated for drug resistance analysis and AMR gene detection. The results indicated that the isolated 90 strains of E. coli have high resistance rates to penicillin, amoxicillin, ampicillin, tetracycline, compound sulfamethoxazole, sulfisoxazole, chloramphenicol, florfenicol, and rifampin (≥70%). Among these antimicrobial drugs, the resistance rate to rifampicin is as high as 100%. Among the isolated 90 strains of E. coli, all of them were resistant to more than two kinds of antimicrobial drugs, the number of strains resistant to nine kinds of drugs was the largest (19 strains), and the most resistant strain showed resistance to 16 kinds of antibacterial drugs. Regarding the AMR genes, among the three aquaculture farms, the most resistance genes were detected in farm II (28 species). The detection rate of blaTEM, blaCIT, blaNDM, floR, OptrA, cmlA, aphA1, Sul2, oqxA, and qnrS in 90 isolates of E. coli was high (≥50%). The detection rate of carbapenem-resistant genes, such as blaKPC, blaIMP, and cfr, was relatively lower ( ≤ 30%), and the detection rate of mcr2 was the lowest (0). At least four AMR genes were detected for each strain, and 15 AMR genes were detected at most. Among them, the number of strains that carried 10 AMR genes was the largest (15 strains). Finally, a correlation analysis found that the AMR genes including blaTEM, blaCIT, floR, OptrA, cmlA, aac(3)-II, Sul2, ereA, ermB, oqxB, qnrA, mcr1, and mcr2 had a high correlation rate with drug resistance (≥50%). To summarize, the 90 strains of E. coli isolated from water, surrounding soil, and sediment samples showed resistance to multi-antimicrobial drugs and carried various antimicrobial resistance genes. Thus, it is essential to strengthen the rational use of antimicrobial drugs, especially the amide alcohol drugs, and control the AMR in the aquaculture industry of Zhanjiang, China.
Highlights
Due to human demand for a variety of animal proteins, the aquaculture industry is developing rapidly [1]
The isolated E. coli strains from the three aquaculture farms all have high antimicrobial drug resistance rates to penicillin and rifampicin, and the resistance rate to rifampicin reaches 100%
The present study investigated the distribution of Antimicrobial resistance (AMR) genes and analyzed the drug resistance of E. coli in aquaculture farms of Zhanjiang and their surrounding environments, and the findings have positive implications for public health
Summary
Due to human demand for a variety of animal proteins, the aquaculture industry is developing rapidly [1]. The residual antibiotics in aquatic products pose a potential risk to food safety, and antibiotics excreted from aquatic animals are dispersed in the water and sediments, leading to the emergence of drug-resistant bacteria and antimicrobial resistance (AMR) genes in aquaculture farms and the surrounding environment [3, 4]. Under the pressure of excessive use of antibiotics, the drug-resistant bacteria even appeared to demonstrate multi-drug resistance, which causes serious negative impacts on public health [5]. The AMR genes spread vertically and spread to other bacteria horizontally through genetic elements, increasing the number of drug-resistant strains and causing difficulties in the treatment of clinical diseases and infection in both humans and animals [7, 8]
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