Chlorine disinfection is a key global public health strategy for the prevention and control of diseases, such as COVID-19. However, little is known about effects of low levels of residual chlorine on freshwater microbial communities and antibiotic resistomes. Here, we treated freshwater microcosms with continuous low concentrations of chlorine and quantified the effects on aquatic and zebrafish intestinal microbial communities and antibiotic resistomes, using shotgun metagenome and 16S rRNA gene sequencing. Although chlorine rapidly degraded, it altered the aquatic microbial community composition over time and disrupted interactions among microbes, leading to decreases in community complexity and stability. However, community diversity was unaffected. The majority of ecological functions, particularly metabolic capacities, recovered after treatment with chlorine for 14 d, due to microbial community redundancy. There were also increased levels of antibiotic-resistance gene dissemination by horizontal and vertical gene transfer under chlorine treatment. Although the zebrafish intestinal microbial community recovered from temporary dysbiosis, growth and behavior of zebrafish adults were negatively affected by chlorine. Overall, our findings demonstrate the negative effects of residual chlorine on freshwater ecosystems and highlight a possible long-term risk to public health.

氯消毒是预防和控制 COVID-19 等疾病的一项重要全球公共卫生战略。然而，关于低水平余氯对淡水微生物群落和抗生素耐药性的影响知之甚少。在这里，我们使用鸟枪宏基因组和 16S rRNA 基因测序，用连续低浓度氯处理淡水微观世界，并量化对水生和斑马鱼肠道微生物群落和抗生素耐药性的影响。尽管氯会迅速降解，但随着时间的推移它会改变水生微生物群落的组成并破坏微生物之间的相互作用，从而导致群落复杂性和稳定性降低。然而，社区多样性并未受到影响。大多数生态功能，特别是代谢能力，由于微生物群落冗余，用氯处理 14 天后恢复。在氯处理下水平和垂直基因转移也增加了抗生素抗性基因的传播水平。尽管斑马鱼肠道微生物群落从暂时的生态失调中恢复过来，但成年斑马鱼的生长和行为受到氯的负面影响。总的来说，我们的研究结果证明了余氯对淡水生态系统的负面影响，并强调了可能对公众健康构成的长期风险。成年斑马鱼的生长和行为受到氯的负面影响。总的来说，我们的研究结果证明了余氯对淡水生态系统的负面影响，并强调了可能对公众健康构成的长期风险。成年斑马鱼的生长和行为受到氯的负面影响。总的来说，我们的研究结果证明了余氯对淡水生态系统的负面影响，并强调了可能对公众健康构成的长期风险。