Assessing the impact of Escherichia coli on recreational water safety using quantitative microbial risk assessment

Recreational water activities have become an integral part of society for entertainment, health, and fitness. The water quality for these activities plays an integral role in the health and safety of the participants. This study aimed to monitor the presence of Escherichia coli in selected recreational water bodies, specifically rowing in the Gauteng Province of South Africa. Water samples were collected (upstream, midstream, and downstream) from three recreational water sites, i.e., Klip Rivier, Wemmer Pan, and Germiston Lake, monthly from May to October 2022. The presence of E. coli was determined using the Colilert^® Quanti-Tray^®/2,000 (IDEXX) assay and ChromoSelect agar. Pathotypes were confirmed using a multiplex PCR. The MPN for E. coli from all the samples exceeded the recommended guidelines of,2,000 microbes/100 mL. Pathogenic E. coli was detected in all three sites, with EPEC, ETEC, EAEC being most prevalent. The E. coli isolates showed 66% ESBL resistance and 94% carbapenemase resistance. Risk assessment showed recreational activities (rowing and swimming) posed a significant health risk as exceeded the annual risk benchmark limit of 1 × 10⁴. The results obtained provide insights into the health risk associated with recreational activities within these water bodies and highlight the need for seasonal monitoring.