Prevalence and antimicrobial resistance of salmonella isolates from backyard chicken in Maryland lower eastern shore, USA

The growing interest in organic, fresh, and locally sourced poultry leads to the expansion of backyard poultry farming. However, recent backyard poultry-linked Salmonella outbreaks have raised significant public health concerns. In this study, we investigated the prevalence, serotype, and antibiotic resistance of Salmonella from backyard poultry as part of a youth development initiative by the University of Maryland Eastern Extension Department's 4-H program. We distributed day-old Ross chicks to participants across Wicomico, Somerset, and Worcester counties in lower Eastern Shore, MD, for hands-on learning, management, and microbiological sampling. A total of 82 samples, including cloacal swabs, litter, environmental sponges, feed, and whole carcasses, were collected from three 4-H participant farms and the poultry processing plant during the study period. Samples were processed using standard microbiological techniques, and Salmonella isolates were confirmed by PCR targeting the invA gene. A total of 13 Salmonella isolates were identified, including S. Infantis (7/13) (1). The prevalence of Salmonella in pre-harvest samples was 6.75 % (5/74), whereas post-harvest samples exhibited a 100 % prevalence (8/8). All 13 isolates were multidrug-resistant (MDR), exhibiting resistance to several antibiotic classes, including penicillins, macrolides, and tetracyclines. This study highlights the prevalence of antibiotic-resistant Salmonella in backyard poultry and stresses the need for strict biosecurity measures, proper hygiene, and education to prevent zoonotic transmission, particularly among children who are the major handlers of backyard chicken thereby promoting public health and food safety.