摘要

      在临床和环境中，抗生素耐药性仍然是一个新出现的威胁。在众多原因中，后氯处理的人类废水对抗生素耐药性的影响尚未得到很好的研究。我们的研究比较了连续三年后含氯废水中气单胞菌对12种抗生素的敏感性。两种水生环境中均以veronii气单胞菌和嗜水气单胞菌为主，但处理后的废水物种多样性明显增强。总的来说，与上游地表水相比，处理后的废水中萘啶酸、甲氧苄啶磺胺甲恶唑（SXT）和四环素耐药菌株以及多药耐药（MDR）菌株的患病率更高。在筛选出四环素耐药菌株后，34.8%的废水分离株和8.3%的地表水分离株具有多药耐药性，以萘啶酸、链霉素和SXT最为常见。四环素耐药菌株中，外排泵基因tetE和tetA最为普遍，但与tetA相关的抗性较强。超过50%的河流和处理过的废水分离物显示出与丝氨酸蛋白酶活性显著相关的细胞毒性，这表明废水中的许多MDR菌株具有致病性。这些发现强调，传统处理的废水仍然是一个抗药性、潜在致病性细菌种群的水库，这些细菌种群被引入水生系统，可能对环境和公众健康构成威胁。
      重要的气单胞菌是革兰氏阴性、无生殖能力的杆状细菌，它们在淡水和咸水中是本地的。它们在变温动物和包括人类在内的哺乳动物中的致病性引起了严重的环境和公共卫生问题，特别是随着抗生素耐药性的上升。废水处理设施是传播抗生素耐药基因（ARGs）和耐药菌群的主要水库，因此是水生生态系统中耐药菌群的潜在主要贡献者。然而，很少有纵向研究分析人类废水及其受纳水体环境之间的抗性。考虑到气单胞菌在水环境中的普遍性，本研究采用气单胞菌作为环境抗微生物指标，并与3年后含氯废水进行了比较。此外，我们评估了这些抗药性人群致病的可能性，从而阐述了它们潜在的公共卫生威胁。

      Antibiotic resistance continues to be an emerging threat both in clinical and environmental settings. Among the many causes, the impact of postchlorinated human wastewater on antibiotic resistance has not been well studied. Our study compared antibiotic susceptibility among Aeromonas spp. in postchlorinated effluents to that of the recipient riverine populations for three consecutive years against 12 antibiotics. Aeromonas veronii and Aeromonas hydrophila predominated among both aquatic environments, although greater species diversity was evident in treated wastewater. Overall, treated wastewater contained a higher prevalence of nalidixic acid-, trimethoprim-sulfamethoxazole (SXT)-, and tetracycline-resistant isolates, as well as multidrug-resistant (MDR) isolates compared to upstream surface water. After selecting for tetracycline-resistant strains, 34.8% of wastewater isolates compared to 8.3% of surface water isolates were multidrug resistant, with nalidixic acid, streptomycin, and SXT being the most common. Among tetracycline-resistant isolates, efflux pump genes tetE and tetA were the most prevalent, though stronger resistance correlated with tetA. Over 50% of river and treated wastewater isolates exhibited cytotoxicity that was significantly correlated with serine protease activity, suggesting many MDR strains from effluent have the potential to be pathogenic. These findings highlight that conventionally treated wastewater remains a reservoir of resistant, potentially pathogenic bacterial populations being introduced into aquatic systems that could pose a threat to both the environment and public health.

       IMPORTANCE Aeromonads are Gram-negative, asporogenous rod-shaped bacteria that are autochthonous in fresh and brackish waters. Their pathogenic nature in poikilotherms and mammals, including humans, pose serious environmental and public health concerns especially with rising levels of antibiotic resistance. Wastewater treatment facilities serve as major reservoirs for the dissemination of antibiotic resistance genes (ARGs) and resistant bacterial populations and are, thus, a potential major contributor to resistant populations in aquatic ecosystems. However, few longitudinal studies exist analyzing resistance among human wastewater effluents and their recipient aquatic environments. In this study, considering their ubiquitous nature in aquatic environments, we used Aeromonas spp. as bacterial indicators of environmental antimicrobial resistance, comparing it to that in postchlorinated wastewater effluents over 3 years. Furthermore, we assessed the potential of these resistant populations to be pathogenic, thus elaborating on their potential public health threat.

       https://aem.asm.org/content/86/3/e02053-19.abstract