摘要

抗生素抗性基因（ARG）在环境中的转移对人类和动物健康都是一种威胁。然而，很少探索噬菌体对通过转导传播抗性基因的贡献。在这项研究中，我们筛选了来自中国三个商业农场猪粪的32种临床相关ARG类型，以评估细菌和噬菌体中ARG群体的存在，并进一步估计噬菌体对抗生素抗性传播的贡献。我们发现噬菌体DNA含有35.5％的目标ARG类型，并且在100％的噬菌体DNA样本中发现了sul1，blaTEM和ermB。细菌群体中最丰富的基因是ermB和fexA，而ermB是噬菌体中最丰富的。相比之下，floR是两个群体中ARG最少的。此外，在该研究中首先使用噬菌体和细菌中ARG丰度的比率指数作为噬菌体传递ARG的能力的估计。 qnrA的比例最大（约10-1），与最丰富的噬菌体ARG ermB不同。此外，fexA具有最低的比值（约10-6）而不是floR。这些结果表明单独使用ARGs丰度和检出率可能不适合全面判断噬菌体对抗生素抗性传播的贡献。更合适的模型是三个指数的应用;发生率，噬菌体的绝对丰度和比值作为在噬菌体中进行环境ARG评估的警告和监测工具。

The transfer of antibiotic resistance genes (ARGs) in the environment is a threat to both human and animal health. However, the contribution of bacteriophages to the dissemination of resistance genes via transduction is rarely explored. In this study, we screened pig feces from three commercial farms in China for 32 clinically relevant ARG types to assess the presence of the ARG population in bacteria and bacteriophage and further to estimate the contribution of bacteriophages to the dissemination of antibiotic resistance. We found that bacteriophage DNA contained 35.5% of the target ARG types and sul1, blaTEM and ermB were found in 100% of the phage DNA samples. The most abundant genes in the bacterial population were ermB and fexA whereas ermB was the most abundant in bacteriophage. In contrast, floR was the least abundant ARG in both populations. Also, the ratio index of the abundance of ARGs in bacteriophage and bacteria was firstly used in this study as an estimator of bacteriophage ability to transmit ARGs. The ratio for qnrA was the greatest (about 10−1) and differed from the most abundant bacteriophage ARG ermB. In addition, fexA had the lowest ratio value (about 10−6) and not floR. These results illustrate that ARGs abundance and detection rates used alone probably be not suitable for comprehensively judging the contribution of bacteriophage to the dissemination of antibiotic resistance. A more suitable model is the application of three indices; occurrence rate, absolute abundance in bacteriophage and the ratio value as warning and monitoring tools for environmental ARG assessments in bacteriophages.

https://www.sciencedirect.com/science/article/pii/S0269749117349187