Antimicrobial Research Unit, College of Health Sciences, University of Kwazulu-Natal, Private Bag X54001, Durban, 4000, South Africa.
Department of Applied Biology and Biochemistry, National University of Science and Technology, P.O Box AC 939 Ascot, Bulawayo, 00263, Zimbabwe.
BMC Microbiol. 2020 Nov 12;20(1):346. doi: 10.1186/s12866-020-02036-7.
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.
在南非等新兴经济体，获得安全饮用水用于饮用和家庭活动仍然是一个挑战，这迫使资源有限的社区使用受微生物污染的河水用于个人和家庭用途，从而带来公共健康风险。本研究定量评估了污水处理厂（WWTP）及其相关地表水的污水中存在的水源性病原体细菌暴露后，WWTP 工人和社区可能面临的细菌污染和潜在健康危害。
采用实时聚合酶链反应靶向 uidA 和 tuf 基因分别对大肠埃希氏菌（Colilert®-18/Quanti-Tray®2000）和肠球菌（Enterolert®/Quanti-Tray®2000）进行定量和明确鉴定。采用近似β泊松剂量反应模型估计致病性大肠埃希氏菌的感染概率（Pi）。所有采样点的大肠埃希氏菌浓度范围为 2.60E+02/100 mL 至 4.84E+06/100 mL；肠球菌浓度范围为 2.60E+02/100 mL 至 3.19E+06/100 mL。从本研究中获得的 580 株大肠埃希氏菌中，89.1%为肠道型，7.6%为肠外致病性大肠埃希氏菌。获得的 579 株肠球菌中，50.4%为粪肠球菌（50.4%），31.4%为屎肠球菌，3.5%为屎肠球菌，0.7%为鹑鸡肠球菌。由于使用这些水进行娱乐和家庭用途而对社区健康造成的健康风险显示，从上游（范围，55.1-92.9%）而非下游（范围，26.8-65.3%）站点摄入 1 毫升河水会带来更大的健康风险（Pi）。工人由于一次意外摄入 1 毫升水而感染致病性大肠埃希氏菌的职业风险为 0%（出水）和 23.8%（原水进水）。如果工人一年内每周多次摄入 1 毫升水，出水和进水的 Pi 分别为 1.2%和 100%。
我们的研究结果表明，在使用研究中的污水处理厂上下游河水的 WWTP 工人和社区中，存在着较高的感染风险。
