Evaluation and quantification of antimicrobial residues and antimicrobial resistance genes in two Italian swine farms. (December 2019)

• Record Type: Journal Article
• Authors: Petrin, Sara; Patuzzi, Ilaria; Di Cesare, Andrea; Tiengo, Alessia; Sette, Giovanni; Biancotto, Giancarlo; Corno, Gianluca; Drigo, Michele; Losasso, Carmen; Cibin, Veronica
• Is Part Of: Environmental pollution. Volume 255(2019)Part 1
• Publication Date: 2019-12
• Subjects: Antimicrobial resistance genes -- Antimicrobial residues -- Swine farming -- Italy -- qPCR; Pollution -- Periodicals; Pollution -- Environmental aspects -- Periodicals; Environmental Pollution -- Periodicals; Pollution -- Périodiques; Pollution -- Aspect de l'environnement -- Périodiques; Pollution -- Effets physiologiques -- Périodiques; Pollution; Pollution -- Environmental aspects; Periodicals; Electronic journals; 363.73
• DOI: 10.1016/j.envpol.2019.113183
• Languages: English
• ISSNs: 0269-7491

Abstract

Abstract: Antimicrobial resistance genes (ARGs) are considered emerging environmental pollutants, posing potential risks for human and animal health: the misuse of antimicrobials in food-producing animals could favour the maintenance and spread of resistances in bacteria. The occurrence of ARGs in Italian swine farming – which has specific characteristics – was investigated in order to explore resistance spread dynamics. Two farrow-to-finish pig farms were longitudinally monitored: faecal samples from animals and environmental samples were collected. DNA was extracted and tet A, erm B, qnr S and mcr 1 ARGs were analysed by qPCR for their ability to confer resistance to highly or critically important antimicrobials (CIAs). Moreover, 16SrDNA gene was analysed to assess bacterial abundance. erm B and tet A genes were found in animal samples and manure samples. On the contrary, mcr 1 was exclusively found in weaners, while qnr S occurred in all animal categories but sows and finishers. Among the analysed genes, erm B and tet A showed the highest absolute and relative abundances. Our results indicate that erm B and tet A ARGs are widely disseminated in the explored farms, suggesting efficient maintenance among bacteria and persistence in the environment. Interestingly, the presence of qnr S and mcr 1, limited to just a few animal categories, highlights inefficient dissemination of these genes in the farm environment, in particular for mcr 1, a stable plasmid gene conferring resistance to the last-resort antimicrobial, colistin. Paying close attention only to the finishing phase would have hampered the discovery of resistances to CIAs at farm level, which we instead identified thanks to an intensive longitudinal monitoring programme. Graphical abstract: Image 1 Highlights: erm B and tet A resistance genes are widely disseminated in Italian swine farms. Limited presence of qnrS and mcr 1 resistance genes to few production phases. Diffuse resistances to CIA for human medicine at farm level. Finishing phase cannot give a comprehensive picture of antimicrobial resistances. Abstract : Monitoring along the entire production chain reveals a more comprehensive picture of antimicrobial resistance genes in Italian swine farming system.