Access to safe water for drinking and domestic activities remains a challenge in emerging economies like South Africa, forcing resource-limited communities to use microbiologically polluted river water for personal and household purposes, posing a public health risk. This study quantified bacterial contamination and the potential health hazards that wastewater treatment plant (WWTP) workers and communities may face after exposure to waterborne pathogenic bacteria in a WWTP and its associated surface water, respectively. Escherichia coli (Colilert®-18/ Quanti-Tray® 2000) and enterococci (Enterolert®/ Quanti-Tray® 2000) were quantified and definitively identified by real-time polymerase chain reaction targeting the uidA and tuf genes, respectively. An approximate beta-Poisson dose-response model was used to estimate the probability of infection (Pi) with pathogenic E. coli. Mean E. coli concentration ranged from 2.60E+ 02/100 mL to 4.84E+ 06/100 mL; enterococci ranged from 2.60E+ 02/100 mL to 3.19E+ 06/100 mL across all sampled sites. Of the 580 E. coli isolates obtained from this study, 89.1% were intestinal, and 7.6% were extraintestinal pathogenic E. coli. The 579 enterococci obtained were 50.4% E. faecalis (50.4%), 31.4% E. faecium, 3.5%, E. casseliflavus and 0.7% E. gallinarum. The community health risk stemming from the use of the water for recreational and domestic purposes revealed a greater health risk (Pi) from the ingestion of 1 mL of river water from upstream (range, 55.1–92.9%) than downstream (range, 26.8–65.3%) sites. The occupational risk of infection with pathogenic E. coli for workers resulting from a once-off unintentional consumption of 1 mL of water was 0% (effluent) and 23.8% (raw influent). Multiple weekly exposures of 1 mL over a year could result in a Pi of 1.2 and 100% for the effluent and influent, respectively. Our findings reveal that there is a potentially high risk of infection for WWTP workers and communities that use river water upstream and downstream of the investigated WWTP.

中文翻译：

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污水处理厂及其受纳地表水体水源性病原体定量微生物风险评估


在南非等新兴经济体中，获得安全的饮用水和家庭活动仍然是一个挑战，迫使资源有限的社区将受到微生物污染的河水用于个人和家庭用途，从而构成公共健康风险。这项研究量化了废水处理厂 (WWTP) 工作人员和社区分别接触污水处理厂及其相关地表水中的水生致病菌后可能面临的细菌污染和潜在健康危害。分别通过针对 uidA 和 tuf 基因的实时聚合酶链式反应对大肠杆菌 (Colilert®-18/ Quanti-Tray® 2000) 和肠球菌 (Enterolert®/ Quanti-Tray® 2000) 进行定量和明确鉴定。使用近似 β-泊松剂量反应模型来估计致病性大肠杆菌感染的概率 (Pi)。平均大肠杆菌浓度范围为 2.60E+ 02/100 mL 至 4.84E+ 06/100 mL；所有采样点的肠球菌范围为 2.60E+ 02/100 mL 至 3.19E+ 06/100 mL。本研究获得的580株大肠杆菌分离株中，89.1%为肠道大肠杆菌，7.6%为肠外致病性大肠杆菌。获得的 579 株肠球菌中，粪肠球菌占 50.4%（50.4%），屎肠球菌占 31.4%，卡氏肠球菌占 3.5%，鸡肠球菌占 0.7%。由于娱乐和家庭用水而产生的社区健康风险显示，从上游摄入 1 毫升河水（范围，55.1-92.9%）的健康风险（Pi）比下游（范围，26.8-92.9%）更大。 65.3%）网站。工人一次性无意消耗 1 mL 水而感染致病性大肠杆菌的职业风险分别为 0%（污水）和 23.8%（原水）。 一年内每周多次接触 1 mL 可能会导致流出物和流入物的 Pi 分别为 1.2 和 100%。我们的研究结果表明，在所调查的污水处理厂上游和下游使用河水的污水处理厂工作人员和社区存在潜在的高感染风险。