摘要
      氯霉素及其残留的过度使用已成为对人类健康和生态安全的潜在威胁。揭示CAP生物降解过程中的关键微生物物种以及微生物群落与抗生素抗性基因（ARGs）的相互作用具有挑战性。本研究试图调查连续间歇反应器（SBR）处理CAP废水过程中微生物群落与ARGs的相互作用，以探索潜在的抗生素耐药性机制。基于核心属Candidatus Competitive bacter和Hydrogenophaga，该处理表现出优异的性能，CAP去除率为95.5%，具有较强的抗生素耐药性和对进水中不断增加的CAP浓度的适应性。同时，Candidatus Competitive bacter和Hydrogenophaga与cml_e3和cml_e8的主要CAP抗性基因显著相关，它们通过外排泵机制产生对CAP压力的抗性。此外，两个CAP外排泵基因（floR和cmlA）在低CAP水平（0.01–0.1 g L−1）下受到刺激，而在高CAP水平（0.2 g L−2）下受到抑制。本研究强调，SBR是一种环保的去除CAP的策略，通过外排泵机制富集竞争Candidatus Competitive bacter和Hydrogenophaga的核心属，以对抗CAP压力。
Abstract
Excessive use of chloramphenicol (CAP) and its residues has emerged as a potential threat to human health and ecological safety. It is challenging to reveal the key microbial species in the CAP biodegradation process and interactions of the microbial community with the antibiotic resistance genes (ARGs). The present study sought to investigate the interactions of microbial community with ARGs during the sequential batch reactor (SBR) treatment of CAP wastewater to explore the potential antibiotic resistance mechanisms. The treatment showed excellent performance with 95.5% CAP removal efficiency based on the core genera of Candidatus Competibacter and Hydrogenophaga with strong antibiotic resistance and adaptability to the increasing CAP concentration in the influent. Meanwhile, Candidatus Competibacter and Hydrogenophaga were significantly associated with the primary CAP resistance genes of cml_e3 and cml_e8, which developed resistance against CAP pressure through efflux pump mechanism. Furthermore, the two CAP efflux pumps genes (floR and cmlA) were stimulated at low CAP level (0.01–0.1 g L−1) while suppressed at high CAP level (0.2 g L−1). This study emphasizes that SBR is an eco-friendly strategy to remove CAP by enriching the core genera of Candidatus Competibacter and Hydrogenophaga through the efflux pump mechanism to against the CAP pressure.

https://www.sciencedirect.com/science/article/abs/pii/S0964830522001743