摘要

流域抗生素耐药率增加的证据引起了全世界的关注。在休闲水域中出现与健康有关的抗生素抗性细菌病原体（ARBPs）的情况有限。迄今尚未表征某些环境因素（例如悬浮颗粒）对抗性传播的影响。本研究采用文化和分子方法相结合的方法，全面研究北京三个休闲湖泊样本中微生物对代表性抗生素的抗性模式。基于梯度浓度测定的抗生素抗性指数（ARI）显示样品显示出对青霉素-G的高抗性，对氨苄青霉素，万古霉素和红霉素的中度抗性以及对头孢曲松，庆大霉素，四环素和氯霉素的低抗性。培养并收集抗生素抗性细菌（ARB），并使用新一代测序（NGS）进一步探索潜在ARBP种类的多样性。结果显示，大多数鉴定的ARBP是具有新出现的临床问题的环境机会致病菌，例如耐多药的不动杆菌（Acinetobacter junii）。此外，颗粒附着（PA）部分表现出比自由漂浮（FL）部分更高的ARI值，表明PA部分对选择的抗生素更具抗性。并且NGS结果显示，与FL级分相比，PA级分在筛选的ARB群落组成中显示出更高的相似性，这主要是由于颗粒提供的保护作用。因此，ARBP可以在保护性粒子基质中持续更长时间。然而，通过qPCR对抗生素抗性基因（ARG）的定量显示两种级分之间没有显着的丰度差异。总体而言，这些研究结果表明，娱乐水域中ARBPs的流行可能带来潜在的健康风险，并且可以更好地了解颗粒在水生系统中抗生素抗性传播中的作用，并通过水管理控制过量悬浮颗粒。

Evidence of the increasing incidence of antibiotic resistance in watersheds has attracted worldwide attention. Limited in formation is available on the occurrences of health-related antibiotic-resistant bacterial pathogens (ARBPs) in recreational waters. The effects of certain environmental factors (e.g., suspended particles) on the spread of resistance also has not been characterized to date. In this study, a combination of culture and molecular methods was employed to comprehensively investigate the patterns of microbial resistance to representative antibiotics in samples from three recreational lakes in Beijing. The antibiotic resistance index (ARI) based on the gradient concentration assay revealed that samples showed high resistance to penicillin-G, moderate resistance to ampicillin, vancomycin and erythromycin and low resistance to ceftriaxone, gentamycin, tetracycline and chloramphenicol. Antibiotic-resistant bacteria (ARB) were cultured and collected, and the diversity of potential ARBP species was further explored using next-generation sequencing (NGS). The results showed that most of the identified ARBPs were environmental opportunistic pathogens with emerging clinical concerns, e.g., the multidrug-resistant Acinetobacter junii. Furthermore, particle-attached (PA) fractions presented higher ARI values than free-floating (FL) fractions did, indicating that the PA fractions were more resistant to selected antibiotics. And the NGS results revealed that the PA fractions showed higher similarity in the screened ARB community compositions in comparison with the FL fractions, primarily due to a protective effect provided by the particles. Accordingly, ARBPs could persist for a longer time in protective particle matrices. However, quantification of antibiotic-resistant genes (ARGs) by qPCR showed no significant abundance differences between the two fractions. Overall, these findings suggest a potential health risk from the prevalence of ARBPs in recreational waters and provides a better understanding of the contribution of particles in the spread of antibiotic resistance in aquatic systems, with implications for the control of excessive suspended particles by water management.

https://www.ncbi.nlm.nih.gov/pubmed/30199799