摘要
      抗生素耐药性是公众健康的一个严重问题。农场环境是抗生素抗性细菌和抗生素抗性基因（ARGs）的相关宿主，因此需要采取策略来限制ARGs从农场向环境的传播。在这项研究中，选择了一个从未将抗生素用于任何目的的肉鸡养殖场，以评估这一措施是否能有效降低农场环境（FE）和肉类加工环境（MPE）中的ARGs负荷。对来自FE和MPE的粪便样品进行处理以进行DNA提取。分别通过PCR和数字液滴PCR（ddPCR）对16S rRNA基因和选定的ARGs（blaTEM、qnrS、sul2和tetA）进行检测和定量。一般来说，FE中定量ARGs的相对丰度与集约化农场中测量的相对丰度相似或更高。此外，除tetA外，FE和MPE之间其他ARG的相对丰度没有差异。这些结果表明，在肉鸡养殖中选择不使用抗生素并不能有效地限制ARGs在MPE中的传播，并且应考虑ARGs的进一步来源，包括之前的生产阶段，特别是繁殖阶段。
ABSTRACT
Antibiotic resistance is a serious concern for public health. Farm environments are relevant reservoirs of antibiotic resistant bacteria and antibiotic resistance genes (ARGs), thus strategies to limit the spread of ARGs from farms to the environment are needed. In this study a broiler farm, where antibiotics have never been used for any purpose, was selected to evaluate if this measure is effective in reducing the ARGs load in farm environment (FE) and in meat processing environment (MPE). Faecal samples from FE and MPE were processed for DNA extraction. Detection and quantification of the 16S rRNA gene and selected ARGs (blaTEM, qnrS, sul2, and tetA) were carried out by PCR and digital droplet PCR (ddPCR), respectively. Generally, the relative abundance of the quantified ARGs in FE was similar or higher than that measured in intensive farms. Furthermore, apart for tetA, no differences in relative abundances of the other ARGs between FE and MPE were determined. These results suggest that the choice to not use antibiotics in broiler farming is not so effective to limit the ARGs spread in MPE and that further sources of ARGs should be considered including the preceding production phase with particular reference to the breeding stage.

https://www.sciencedirect.com/science/article/pii/S0032579121006957