Cangola Jenita, Abagale Felix K, Cobbina Samuel J, Osei Richard A
West African Centre for Water, Irrigation and Sustainable Agriculture (WACWISA), University for Development Studies, P. O. Box TL 1882, Tamale, Ghana; Department of Environment and Sustainability Sciences, University for Development Studies, Tamale, Ghana; Faculty of Environmental Engineering and Natural Resources, Zambezi University, Manica, Mozambique.
West African Centre for Water, Irrigation and Sustainable Agriculture (WACWISA), University for Development Studies, P. O. Box TL 1882, Tamale, Ghana; Department of Agricultural Engineering, University for Development Studies, P. O. Box TL 1882, Tamale, Ghana.
Int J Hyg Environ Health. 2025 Jan;263:114478. doi: 10.1016/j.ijheh.2024.114478. Epub 2024 Oct 5.
The use of wastewater for non-potable purposes is an important alternative for addressing water scarcity, especially in developing regions. However, minimizing the risks, particularly those associated with emerging contaminants that may induce resistance among pathogens in wastewater, is crucial. This study assessed the occurrence of antibiotic-resistant bacteria in untreated wastewater used for agricultural purposes and evaluated the quantifiable health risks associated with this practice in Tamale, Ghana. The resistance of some Enterobacteriaceae, such as E. coli, Klebsiella, and Salmonella-Shigella, to four commonly used antibiotics in Ghana was assessed using a conventional microbiological culture approach and the Kirby Bauer disk diffusion method. A Quantitative Microbial Risk Assessment (QMRA) was performed to estimate the health risks associated with two distinct scenarios of wastewater reuse: (1) accidental ingestion of contaminated wastewater and soil, and (2) consumption of vegetables irrigated with wastewater. This approach applied a Monte Carlo simulation based on 10,000 interactions and identified E. coli O157:H7 as the reference pathogen. Among Enterobacteriaceae, Klebsiella pneumoniae, Salmonella-Shigella and E. coli were isolated, in concentrations exceeding the limit recommended by the World Health Organization (10 CFU/100 ml). All the isolated bacteria were resistant to metronidazole (5 μg). Thirty-three per cent of Klebsiella pneumoniae isolates were intermediate/moderately susceptible, and all other bacteria were resistant to amoxicillin (30 μg). All Klebsiella pneumoniae and the majority of Salmonella-Shigella (69.8 %) isolates were resistant to trimethoprim-sulfamethoxazole (25 μg) and tetracycline (30 μg). When assessing health risks, the mean annual probability of infection associated with consuming vegetables irrigated with wastewater varied between 5.14 × 10 and 9.79 × 10 per person per year. Conversely, for the accidental ingestion scenario, the probability was 1.00 per person per year. In these scenarios, the probability of illness ranged from 1.29 × 10 to 2.4 × 10 and 2.5 × 10 per person per year. The health risks posed by these findings surpass the maximum threshold prescribed by the World Health Organization, thereby emphasizing the need for prompt mitigation strategies.
将废水用于非饮用水用途是解决水资源短缺问题的重要替代方案，尤其是在发展中地区。然而，将风险降至最低，特别是与可能导致废水中病原体产生抗性的新兴污染物相关的风险，至关重要。本研究评估了用于农业目的的未经处理废水中抗生素抗性细菌的存在情况，并评估了加纳塔马利这种做法所带来的可量化健康风险。使用传统微生物培养方法和 Kirby Bauer 纸片扩散法评估了一些肠杆菌科细菌，如大肠杆菌、克雷伯菌和沙门氏菌 - 志贺氏菌对加纳常用的四种抗生素的抗性。进行了定量微生物风险评估（QMRA），以估计与两种不同的废水再利用情景相关的健康风险：（1）意外摄入受污染的废水和土壤，以及（2）食用用废水灌溉的蔬菜。该方法基于 10000 次相互作用应用了蒙特卡罗模拟，并将大肠杆菌 O157:H7 确定为参考病原体。在肠杆菌科细菌中，分离出了肺炎克雷伯菌、沙门氏菌 - 志贺氏菌和大肠杆菌，其浓度超过了世界卫生组织推荐的限值（10 CFU/100 ml）。所有分离出的细菌对甲硝唑（5 μg）均有抗性。33% 的肺炎克雷伯菌分离株为中度敏感，所有其他细菌对阿莫西林（30 μg）均有抗性。所有肺炎克雷伯菌和大多数沙门氏菌 - 志贺氏菌（69.8%）分离株对甲氧苄啶 - 磺胺甲恶唑（25 μg）和四环素（30 μg）均有抗性。在评估健康风险时，食用用废水灌溉的蔬菜相关的年平均感染概率在每人每年 5.14×10 至 9.79×10 之间。相反，对于意外摄入情景，概率为每人每年 1.00。在这些情景中，患病概率在每人每年 1.29×10 至 2.4×10 和 2.5×10 之间。这些研究结果所带来的健康风险超过了世界卫生组织规定的最大阈值，从而强调了迅速采取缓解策略的必要性。
