Risk factors associated with Salmonella specific antimicrobial resistance: animal and meat samples

Abstract

Abstract The food system is seen as a major source of antimicrobial resistance (AMR), a threat that has led to an increase of the global burden of infectious diseases. Thus, AMR occurrence was studied in animals and derived meat from Portugal, 2014-2018. AMR surveillance data from Portugal was used. Salmonella AMR was estimated for broilers, laying hens, broiler and pig meat. AMR associated factors were studied: population, year, season, sampler, (HACCP, industry, official, official/industry). AMR occurrence in more than half isolates was assessed using a multivariate logistic regression and a backward stepwise method for each antimicrobial class model, presenting adjusted odds ratio (aOR) and 95% confidence intervals (95%CI). This study included 832 Salmonella isolates. Resistance to more than half isolates was observed to (fluoro)quinolones (broilers:52%; broiler meat:53%), penicillins (pig meat:56%), tetracyclines (pig meat:80%), sulphonamides (pig meat:62%). AMR was more likely to occur to penicillins, tetracyclines, sulphonamides in broiler meat (respectively, aOR 3.18;95%CI 1.95-5.18, 3.38;95%CI 1.27-9.19, 2.46;95%CI 1.44-4.19) and pig meat (respectively, aOR 9.39;95%CI 6.01-14.51, 53.84;95%CI 21.61-144.91, 14.58;95%CI 9.16-23.66), compared to broilers. A lesser AMR chance was observed to (fluoro)quinolones in 2017 and 2018 (respectively, aOR 0.07;95%CI 0.00-0.36, 0.13;95%CI 0.06-0.24) while a higher chance was found to tetracyclines in 2016 and 2018 (respectively, aOR 8.08;95%CI 2.25-30.74, 2.56;95%CI 1.14-6.00), compared to 2014. A higher chance for resistance was detected in spring to (fluoro)quinolones (aOR 2.32;95%CI 1.23-4.46) and penicillins (aOR 2.11;95%CI 1.20-3.78) and summer to (fluoro)quinolones (aOR 2.77;95%CI 1.46-5.35), compared to winter. These results indicate a need to reinforce biosecurity and disease prevention during spring and summer to tackle penicillins, tetracyclines and sulphonamides AMR in animal meat, but also (fluoro)quinolones in broilers. Key messages Biosecurity and prevention measures need to be reinforced during spring and summer to mitigate Salmonella AMR occurrence across the food system. Critical AMR occurrence to (fluoro)quinolones was found to be more associated with broilers.