Department of Environmental Health and Technology, School of Public Health, Walailak University, Nakhon Si Thammarat, 80160, Thailand; One Health Research Center, Walailak University, Nakhon Si Thammarat, 80160, Thailand.
Research Laboratory of Biotechnology, Chulabhorn Research Institute, Bangkok, 10210, Thailand.
Int J Hyg Environ Health. 2021 Sep;238:113859. doi: 10.1016/j.ijheh.2021.113859. Epub 2021 Oct 14.
Antibiotic-resistant bacteria (ARB) and antibiotic resistance genes (ARGs) are pollutants of worldwide concern that threaten human health and ecosystems. Anthropogenic activities and wastewater could be ARB and ARG pollution sources; however, research on ARG abundance and microbial source tracking (MST) of contamination in tropical marine waters is limited. This study examined spatiotemporal variations of six ARGs (bla, bla, bla, mcr-1, sul1, and tetQ) against the widely used antibiotic groups and a class 1 integron-integrase gene (intI1) at two Thai tropical recreational beaches (n = 41). Correlations between ARGs and sewage-specific MST markers (i.e., crAssphage and human polyomaviruses [HPyVs]) and fecal indicator bacteria (i.e., total coliforms, fecal coliforms, and enterococci) were also investigated. Bla, intI1, sul1, and tetQ were ubiquitous at both beaches (85.4-100% detection rate); intI1 was the most abundant (3-6 orders in log copies/100 mL), followed by bla (2-4 orders), sul1 (2-3 orders), and tetQ (2-4 orders). Bla was found in 7.3% (up to 4 orders), and no mcr-1 was detected. Interestingly, bla was prevalent at one beach (2-5 orders; n = 17), but found in only one sample at the other (4 orders). Temporal, but not spatial, differences were noticed; bla was at higher levels in the wet season. IntI1 correlated with sul1 and tetQ (Spearman's rho = 0.47-0.97), suggesting potential horizontal gene transfer. CrAssphage, but not HPyVs, correlated with intI1, sul1, and tetQ (Spearman's rho = 0.50-0.74). Higher numbers of ARGs tended to co-occur in samples with higher crAssphage concentrations, implying sewage contribution to the marine water, with a persisting ARG background. This study provides insight into the ARG pollution status of tropical coastal waters and suggests crAssphage as a proxy for ARG pollution, which could facilitate effective management policies to minimize ARG dissemination in marine environments.
抗药性细菌（ARB）和抗生素抗性基因（ARGs）是全球关注的污染物，威胁着人类健康和生态系统。人为活动和废水可能是 ARB 和 ARG 的污染来源；然而，关于热带海洋水中 ARG 丰度和微生物源追踪（MST）污染的研究有限。本研究在泰国两个热带娱乐海滩（n=41）检测了针对广泛使用的抗生素组的六种 ARGs（bla、bla、bla、mcr-1、sul1 和 tetQ）以及一个 1 类整合子整合酶基因（intI1）的时空变化。还研究了 ARGs 与污水特异性 MST 标记物（即 crAssphage 和人多瘤病毒 [HPyVs]）和粪便指示细菌（即总大肠菌群、粪大肠菌群和肠球菌）之间的相关性。bla、intI1、sul1 和 tetQ 在两个海滩均普遍存在（检出率 85.4-100%）；intI1 最为丰富（3-6 个对数拷贝/100 mL），其次是 bla（2-4 个对数）、sul1（2-3 个对数）和 tetQ（2-4 个对数）。bla 在 7.3%的样本中存在（高达 4 个对数），且未检测到 mcr-1。有趣的是，bla 在一个海滩普遍存在（2-5 个对数；n=17），而在另一个海滩仅在一个样本中存在（4 个对数）。注意到时间而非空间的差异；bla 在雨季水平较高。intI1 与 sul1 和 tetQ 相关（Spearman's rho=0.47-0.97），表明存在潜在的水平基因转移。crAssphage 但不是 HPyVs 与 intI1、sul1 和 tetQ 相关（Spearman's rho=0.50-0.74）。在 crAssphage 浓度较高的样本中，更多的 ARG 倾向于共同出现，暗示污水对海洋水的贡献，存在持续的 ARG 背景。本研究深入了解了热带沿海水域的 ARG 污染状况，并提出 crAssphage 作为 ARG 污染的替代物，这有助于制定有效的管理政策，以最大限度地减少海洋环境中 ARG 的传播。
