Drinking water and biofilm as sources of antimicrobial re-sistance in free-range organic broiler farms.

first_page settings Order Article Reprints Open AccessArticle Drinking Water and Biofilm as Sources of Antimicrobial Resistance in Free-Range Organic Broiler Farms by Alessandra Piccirillo 1,* [ORCID] , Roberta Tolosi 1, Lapo Mughini-Gras 2,3, Jannigje G. Kers 3 [ORCID] and Andrea Laconi 1 [ORCID] 1 Department of Comparative Biomedicine and Food Science, University of Padua, Viale dell’Università 16, 35020 Legnaro, Italy 2 Center for Infectious Disease Control, National Institute for Public Health and the Environment (RIVM), Antonie van Leeuwenhoeklaan 9, 3721 BA Bilthoven, The Netherlands 3 Faculty of Veterinary Medicine, Utrecht University, Yalelaan 2, De Uithof, 3584 CL Utrecht, The Netherlands * Author to whom correspondence should be addressed. Antibiotics 2024, 13(9), 808; https://doi.org/10.3390/antibiotics13090808 Submission received: 14 June 2024 / Revised: 21 August 2024 / Accepted: 24 August 2024 / Published: 26 August 2024 (This article belongs to the Special Issue Molecular Mechanism of Antibiotic Resistance in Microbial Biofilms) Download keyboard_arrow_down Browse Figures Versions Notes Abstract Drinking water distribution systems (DWDSs) represent an ideal environment for biofilm formation, which can harbor pathogenic and antimicrobial-resistant bacteria. This study aimed to assess longitudinally the microbial community composition and antimicrobial resistance (AMR), as determined by 16S rRNA NGS and qPCR, respectively, in drinking water (DW) and biofilm from DWDSs, as well as faeces, of free-range organic broiler farms. The role of DWDSs in AMR gene (ARG) dissemination within the farm environment and transmission to animals, was also assessed. DW and biofilm microbial communities differed from those of faecal samples. Moreover, potentially pathogenic and opportunistic bacteria (e.g., Staphylococcaceae) were identified in water and biofilms. High prevalence and abundance of ARGs conferring resistance to carbapenems (i.e., blaNDM), 3rd and 4th generation cephalosporins (i.e., blaCMY-2), (fluoro)quinolones (i.e., qnrS), and polymyxins (i.e., mcr-3 and mcr-5) were detected in DW, biofilm, and faecal samples, which is of concern for both animal and human health. Although other factors (e.g., feed, pests, and wildlife) may contribute to the dissemination of AMR in free-range organic poultry farms, this study indicates that DWDSs can also play a role.