摘要

    牲畜和家禽粪便是抗生素抗性细菌和抗生素抗性基因（ARG）的主要库。利奈唑胺是用于人类的临床药物，从未批准用于家畜。有趣的是，已经在动物来源的细菌中检测到了三种利奈唑胺抗性基因（cfr，optrA和poxtA），引起了公众的关注。本研究使用实时定量聚合酶链反应研究了中国157个大型农场粪便中三种ARGs（cfr，optrA和poxtA）的丰度。使用超高效液相色谱-串联质谱法测定了利奈唑胺，氟苯尼考，提莫林和缬草胺的残留浓度。共有140个牧场的ARGs检测呈阳性，阳性检出率为89.17％。 OptrA是最常检测到的ARG。家禽和猪粪中的ARGs的多样性和丰度明显高于牛粪。冗余分析表明，氟苯尼考与研究中的所有三个ARG之间都具有很强的关联性，而头孢菌素与optrA呈显着相关性。我们的结果表明，氟苯尼考的残留浓度对家畜粪便中的三种ARG的分布有重要影响，而大量使用氟苯尼考可能会导致产生利奈唑胺抗性基因。

    Livestock and poultry manures are major reservoirs of antibiotic-resistant bacteria and antibiotic resistance genes (ARGs). Linezolid is a clinical medicine for humans and has never been approved for use in livestock. Interestingly, three linezolid resistance genes (cfr, optrA, and poxtA) have been detected in bacteria of animal origin, arousing public concern. This study investigated the abundance of three ARGs, cfr, optrA, and poxtA, in manures from 157 large-scale farms in China using real-time quantitative polymerase chain reaction. The residual concentrations of linezolid, florfenicol, tiamulin, and valnemulin were determined using ultra-high performance liquid chromatography-tandem mass spectrometry. A total of 140 livestock farms were tested positive for ARGs, and the positive detection rate was 89.17 %. OptrA was the most commonly detected ARG. The diversity and abundance of ARGs were significantly higher in poultry and swine manure than in bovine manure. Redundancy analysis presented a strong association between florfenicol and all the three ARGs targeted in the study, and tiamulin showed a significant correlation with optrA. Our results indicated that the residual concentration of florfenicol had a major effect on the distribution of the three ARGs in livestock manures, and extensive use of florfenicol may lead to the production of linezolid resistance genes.

    https://www.sciencedirect.com/science/article/abs/pii/S0304389420310487