Antibiotic resistant <i>E.coli</i> in waterborne matrices nearby intensive farming: One Health Hub project

Abstract The One Health Hub project aims to investigate the presence of antibiotic resistant (AR) E.coli in 5 irrigation channels and 2 private wells, in a northern Italian rural area, characterized by intensive cattle and pig farms. Water sampling occurred seasonally between 2022 and 2023. E.coli was isolated on a chromogenic agar, biochemically identified and analyzed for phenotipic resistance with the VITEK®2 card AST-N380 (Biomerieux), according to EUCAST thresholds. 17 antibiotics were tested: 3 Penicillins, 7 Cephalosporins (1st, 2nd and 3rd gen), 1 Carbapenem, 4 Aminoglycosides, 1 Fluoroquinolone, and 1 Miscellaneous agent. E.coli ranges from 170 to 10.000 CFU/100ml in 33 water samples. Fifty-nine out of 91 (64.8%) strains were sensitive to all antibiotics, while the remaining 32/91 (35.2%) were resistant at least to 1 antibiotic belonging to all classes, except Carbapenems. Major resistance was found towards Penicillins (18%), followed by miscellaneous agents (10%), Cephalosporins (6%), Fluoroquinolone and Aminoglycosides (4%). MDR (≥3antibiotics) was observed in 20/32 (62.5%) strains and ESBL in 9/91 (10%). In all detected rural channels AR E.coli were found, as well as, in the 2 wells. Notably, in these latter, E.coli was both positive for ESBL and resistant to Cephalosporins of 2nd and 3rd generation. This research clearly demonstrates the phenomenon of the spread of AR in the waterborne matrices, even for new antibiotics. The WHO considers AR as a relevant One Health issue, due to the relationship among human, animal and ecosystem domains. The role of water as a vehicle of AR bacteria is evident, assuming the hypothetical pathway of AR bacteria of both human and animal origin contaminating irrigation channels, and thus the vegetables, or when contaminated wells supply water to food-producing animals. Animal effluents are usually distributed in the nearby fields and the runoff of water during rainfall could contaminate irrigation channels also through this way. Funding support provided by the Grandi Sfide di Ateneo 2021. Key messages • Water from irrigation channels and wells has a role in the spreading of AR. • Relative high prevalence of E.coli resistant to antibiotics, comprising 3rd gen Cephalosporins and Fluoroquinolones. In the 2024 abstract supplement of the EPH Conference “Sailing the Waves of European public health: Exploring a Sea of Innovation” in Lisbon, 12–15 November 2024 (https://academic.oup.com/eurpub/issue/34/Supplement_3), we unfortunately failed to publish one abstract. Please find the abstract below.