Health-based risk assessment and surveillance benchmarks for antibiotic-resistant E. coli in treated hospital effluents
Issued Date
2026-06-01
Resource Type
ISSN
14384639
eISSN
1618131X
Scopus ID
2-s2.0-105036235097
Journal Title
International Journal of Hygiene and Environmental Health
Volume
275
Rights Holder(s)
SCOPUS
Bibliographic Citation
International Journal of Hygiene and Environmental Health Vol.275 (2026)
Suggested Citation
Denpetkul T., Srathongneam T., Sittipunsakda O., Tancharoen S., Krabkran P., Mongkolsuk S., Sirikanchana K. Health-based risk assessment and surveillance benchmarks for antibiotic-resistant E. coli in treated hospital effluents. International Journal of Hygiene and Environmental Health Vol.275 (2026). doi:10.1016/j.ijheh.2026.114800 Retrieved from: https://repository.li.mahidol.ac.th/handle/123456789/116387
Title
Health-based risk assessment and surveillance benchmarks for antibiotic-resistant E. coli in treated hospital effluents
Corresponding Author(s)
Other Contributor(s)
Abstract
Hospital effluents are a potential urban source of antimicrobial-resistant bacteria (ARB), yet no discharge criteria exist. We combined national surveillance data from Thailand with forward and reverse quantitative microbial risk assessment (QMRA) to evaluate risks from extended-spectrum β-lactamase (ESBL)-producing Escherichia coli. Forward QMRA considered swimmer exposure by age group and three dose–response models (non-resistant, resistant, and highly virulent proxies). Median risks for non-resistant and resistant surrogates were very low (∼10−9 pppe), but under the virulent proxy, the 95th percentile exceeded the U.S. EPA benchmark of 0.036 pppe for children (0.0486), men (0.0391), and closely in women (0.026). Reverse QMRA translated this benchmark into effluent thresholds: with dilution, values exceeded 108 CFU/100 mL and were not useful for monitoring, while no-dilution scenarios yielded thresholds near 105 CFU/100 mL for resistant surrogates and ∼101 CFU/100 mL for the virulent model, with a worst-case of 20 CFU/100 mL. Based on these results, 100 CFU/100 mL was identified as a feasible surveillance criterion, protective for children and measurable with culture-based methods, with 1000 CFU/100 mL suggested as an action level. This study provides new health-based benchmarks for resistant bacteria in treated hospital effluents and offers an urban-relevant framework for linking microbial risk modeling with AMR surveillance and future effluent standard development.