摘要
      本研究的目的是评估阿莫西林和硫酚处理后鸡肠道中微生物群落和抗微生物耐药性基因（ARGs）的动态以及ARGs的潜在共同选择。为此，使用16S rRNA NGS测定了微生物群落组成，并使用qPCR测定了对β-内酰胺类和酚类产生耐药性的ARGs的丰度。结果显示，施用的抗菌药物并没有显著降低肠道微生物群的多样性，但改变了其组成，治疗后分类群（如Gallibacterium和Megamonas）得到富集，并取代了其他细菌（如链球菌和双歧杆菌）。ARGs（如cmlA、blaCMY-2和blaSHV）与特定分类群（如乳杆菌和亚细颗粒菌）的相对丰度呈正相关。阿莫西林和噻mphenicol施加的选择性压力导致ARG丰度增加，从而对β-内酰胺类（如blaTEM-1、blaSHV和blaCTX-M1样）和酚类（如floR和cmlA）产生耐药性。这些发现，再加上对两类抗菌药物（如blaTEM-1和cmlA）产生耐药性的基因的共存，表明抗菌药物之间可能存在耐药性出现的相互作用，这可能是由于携带多种耐药性决定因素的移动遗传元件（MGE）的存在。
Abstract
The aim of this study was to assess the dynamics of microbial communities and antimicrobial resistance genes (ARGs) in the chicken gut following amoxicillin and thiamphenicol treatments and potential co-selection of ARGs. To this purpose, the microbial community composition, using 16S rRNA NGS, and the abundance of ARGs conferring resistance to β-lactams and phenicols, using qPCRs, were determined. Results revealed that the administered antimicrobials did not significantly reduce the gut microbiota diversity, but changed its composition, with taxa (e.g. Gallibacterium and Megamonas) being enriched after treatment and replacing other bacteria (e.g. Streptococcus and Bifidobacterium). Positive correlations were found between ARGs (e.g. cmlA, blaCMY-2, and blaSHV) and the relative abundance of specific taxa (e.g. Lactobacillus and Subdoligranulum). The selective pressure exerted by both amoxicillin and thiamphenicol resulted in an increased abundance of ARGs conferring resistance to β-lactams (e.g. blaTEM-1, blaSHV, and blaCTX-M1-like) and phenicols (e.g. floR and cmlA). These findings, together with the co-occurrence of genes conferring resistance to the two antimicrobial classes (e.g. blaTEM-1 and cmlA), suggest a possible interaction among antimicrobials on resistance emergence, possibly due to the presence of mobile genetic elements (MGEs) carrying multiple resistance determinants.

https://www.nature.com/articles/s41598-022-24927-7