Previous activity in this study aimed to evaluate the impact of the Raised without Antibiotics (RWA) program on pig production focused on quantifying the overall antibiotics use both in participating RWA and non-RWA barns. Next steps involved the assessment of prevalence of antimicrobial resistance (AMR) and pathogen abundance, by conducting long-term surveillance of AMR and pathogens using whole genome sequencing (WGS), quantifying the resistome, virulome and bacterial diversity in the RWA and non-RWA barns.
Preliminary results from comparative analysis of the ARGs frequency readouts showed significant differentiation between RWA and non- RWA program effects. Specifically, a significant reduced frequency of ARGs for beta-lactams, multi-drug resistance (MDR), phenicol and tetracycline, was observed in manure samples of RWA barns and for phenicol and tetracycline ARG in RWA-piglet feces. On the other hand, data showed a greater frequency of tetracycline-ARG class in the nasopharynx of sows in RWA barns. In terms pathogen prevalence, we found a similar pattern between the non-RWA and RWA barns in the piglet feces and the barn manure samples. Overall, our longitudinal study suggests that raising RWA pigs may have an impact on the prevalence of pathogens and AMR. Results also suggest the possibility to correlate RWA practices with variations in specific sets of AMR classes and pathogens – leading to potentially adjusting RWA measures and practices to target the reduction of certain AMR classes and the persistence of specific pathogens.
Assessing the impact of intervention measures for reducing antibiotic use (full article)
