Antimicrobial Resistance and Zoonoses: One Health Challenge

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Antimicrobial Resistance and Zoonotic Bacteria: Assessing interventions, risk factors and the occurrence of antimicrobial resistance in the food chain production in Portugal

Publication . Costa, Miguel Mendes da; Leite, Andreia; d'Anjo, Maria Cara

Background: Resistant microorganisms that spread in the food system are a major threat to animal health and public health since they are a potential pathway of transmission to humans. This thesis evaluates: (i) antimicrobial resistance (AMR) prevalence and associated risk factors in the Portuguese food system (ii) effectiveness of interventions designed to reduce and adequate antimicrobial usage in animal production and tackle AMR. Methods: Portuguese AMR surveillance program on animals and food products data, 2014-2019, were used to estimate prevalence of AMR in Escherichia coli, Campylobacter and Salmonella samples, factors associated with Salmonella resistance, and AMR profiles. Logistic regression and clustering methods were applied. Effectiveness was assessed in a systematic review with meta-analysis. Articles were identified on PubMedTM, ScopusTM, The Cochrane LibraryTM, Web of ScienceTM, and grey literature on DANS EASYTM, WorldCatTM, RCAAPTM. Effectiveness was estimated by intervention, bacterial species, production type and population through fixed and random-effects models. Results: High prevalence of Salmonella resistance was observed, especially during summer and in post farm-stages to most antimicrobials and in summer and farms to fluoroquinolones and quinolones-F(Q). Salmonella F(Q) resistance was associated with broilers. Clusters suggested an escalating multi-drug resistance (MDR) behavior from farm to post-farm stages. Our review indicates that organic and antimicrobial-free farms, and group treatment restrictions lead to AMR reduction. Conclusions: Further attention is needed in the Portuguese food system regarding AMR behavior in particular in post-farm stages due to the potential source of MDR bacteria. Our findings support policy- and decision-making on effective interventions to reduce AMR. Keywords: food-producing animals; antimicrobial resistance; zoonotic bacteria; surveillance; food security; One Health.

2023-09-29Doctoral thesis

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