Occurrence and Quantitative Microbial Risk Assessment of Methicillin-Resistant Staphylococcus aureus (MRSA) in a Sub-Catchment of the Yodo River Basin, Japan

Abstract

The occurrence of Staphylococcus aureus (S. aureus) and methicillin-resistant S. aureus (MRSA) in a sub-catchment of the Yodo River Basin, a representative water system of a drinking water source in Japan, was investigated. The chromogenic enzyme-substrate medium method was used for the detection of S. aureus and MRSA by the presence or absence of antimicrobials in the medium for viable bacteria in a culture-based setting. The contributions of S. aureus and MRSA from wastewater to the rivers were estimated based on mass flux-based analysis, and quantitative microbial risk assessment (QMRA) was further conducted for S. aureus and MRSA in river environments. The mean abundance of S. aureus and MRSA was 31 and 29 CFU/mL in hospital effluent, 124 and 117 CFU/mL in sewage treatment plant (STP) influent, 16 and 13 CFU/mL in STP effluent, and 8 and 9 CFU/mL in river water, respectively. Contribution of the pollution load derived from the target STP effluent to river water ranged from 2% to 25%. The QMRA showed that to achieve the established health benchmarks, the drinking water treatment process would need to yield 1.7 log10 and 2.9 log10 inactivation in terms of infection risk and disability-adjusted life year (DALY) indexes, respectively. These findings highlight the link between medical environment and the importance of environmental risk management for antimicrobial-resistant bacteria in aquatic environments.

Wastewater treatment plants, an “escape gate” for ESCAPE pathogens

“…The genetic analysis of the S. aureus isolates obtained after treatment showed diversity in the spa type and carriage of MGEs, suggesting that treatment could facilitate persistence, evolution, and genetic shifts ( Amirsoleimani et al, 2019 ). A recent study evaluated the occurrence and environmental health risk of S. aureus and MRSA from hospital effluent to sewage treatment plant (STP) and finally to river water at the basin level; a high abundance of over 90% has been detected in the sewage treatment plant, and the contribution of the pollution load derived from the target STP effluent to river water ranged from 2 to 25% ( Azuma et al, 2022 ).…”

The Threat of Methicillin Resistant Staphylococcus aureus (MRSA) in the Aquatic Environment via Wastewater Generated from Healthcare Facilities

“…The World Health Organization (WHO) released a list of 12 particular groups of antimicrobial resistant bacteria (AMRB). Methicillin-resistant Staphylococcus aureus (MRSA) is listed as a highpriority bacterium among these AMRB, following carbapenem-resistant Acinetobacter baumannii, carbapenem-resistant Pseudomonas aeruginosa, and carbapenem-resistant/ third generation cephalosporin-resistant Enterobacterales that are listed as critical priorities [67]. One of the most significant aspects of the epidemiology of MRSA is the global onset and dissemination of the disease caused by these pathogens.…”

TiO2 nanopowder and nanofilm catalysts in the disinfection and mineralization of S. aureus with solar-simulated radiation

“…Water sources are subject to many types of hazardous pollutants, including chemical 1 and biological species. 2,3 Water remediation is thus necessary to eliminate various contaminants and microorganisms, especially from drinking water. 4 For this purpose, various methods are followed at the research and commercial level, including chlorination, 5 peroxidation, 6 UV irradiation, 7 reverse osmosis 8 and others.…”