摘要

       土壤中的抗生素抗性基因 (ARG) 被认为是地球上最大的环境抗性基因之一。由于这些基因可能通过水平基因转移 (HGT) 在微生物中传播，并且在某些情况下是由临床病原体获得的，因此有关其多样性、流动性和编码抗性谱的知识越来越受到公众的关注。这些知识为改进风险预测和制定应对抗生素耐药性的策略提供了机会，并可能有助于指导新型抗生素的设计，在进一步的耐药性到达医院或动物部门之前。在这里，包含培养微生物基因的宏基因组文库，但重要的是，也包括未培养微生物大多数携带的基因，筛选了来自森林和草原土壤的新型 ARG。我们检测到三个新的 β-内酰胺、一个迄今为止未知的氯霉素、一个新的磷霉素，以及三个以前未发现的甲氧苄啶抗性基因。这些 ARG 来自系统发育多样的土壤细菌，并预测编码抗生素失活、抗生素流出或靶酶的替代变体。此外，推导的基因产物与参考数据库条目的最低同一性约为 21%，并具有高水平的抗性。这凸显了功能宏基因组学在从土壤生态系统中发现新型 ARG 方面的巨大潜力。查看全文

       Antibiotic resistance genes (ARGs) in soil are considered to represent one of the largest environmental resistomes on our planet. As these genes can potentially be disseminated among microorganisms via horizontal gene transfer (HGT) and in some cases are acquired by clinical pathogens, knowledge about their diversity, mobility and encoded resistance spectra gained increasing public attention. This knowledge offers opportunities with respect to improved risk prediction and development of strategies to tackle antibiotic resistance, and might help to direct the design of novel antibiotics, before further resistances reach hospital settings or the animal sector. Here, metagenomic libraries, which comprise genes of cultivated microorganisms, but, importantly, also those carried by the uncultured microbial majority, were screened for novel ARGs from forest and grassland soils. We detected three new beta-lactam, a so far unknown chloramphenicol, a novel fosfomycin, as well as three previously undiscovered trimethoprim resistance genes. These ARGs were derived from phylogenetically diverse soil bacteria and predicted to encode antibiotic inactivation, antibiotic efflux, or alternative variants of target enzymes. Moreover, deduced gene products show a minimum identity of ~21% to reference database entries and confer high-level resistance. This highlights the vast potential of functional metagenomics for the discovery of novel ARGs from soil ecosystems. View Full-Text

https://www.mdpi.com/2079-6382/10/4/378