P-023 - Exploring antibiotic resistance in plant-pathogenic bacteria on peach orchards in Pennsylvania

Bacterial spot of peaches is caused by the bacterium Xanthomonas arboricola pv. pruni (Xap), a disease reported in Pennsylvania (PA). A major challenge in managing this pathogen is the limited availability of resistant peach varieties and the demand for susceptible ones, which has led growers to control the disease with oxytetracycline (OTC) and copper-based products (Cu). The extensive use of these antibiotics could increase genetic pressure on Xap and other bacterial communities, potentially leading to antimicrobial resistance (AMR) to OTC and Cu. AMR is an environmental concern, as it affects non-target bacterial communities. Therefore, it is crucial to assess the tolerance levels and genetic mechanisms of antibiotic resistance in Xap and other bacterial communities in peach orchards in PA to improve management strategies and minimize resistance development. This project aimed to: (i) evaluate antibiotic tolerance of bacterial isolates from peach orchard through sensitivity screening assay, (ii) identify resistance genes present in bacterial whole genome isolates, and (iii) assess the AMR awareness among workers in PA agricultural systems. Among the 70 isolates screened for OTC and Cu tolerance, five tolerant isolates were sequenced to characterize their whole genomes and the genes involved in antibiotic resistance. This research could enhance more effective disease management strategies, highlighting the risks associated with antibiotic use in agriculture and emphasizing that AMR is not only an environmental concern but also a public health concern.