Principal Investigator: Kevin Cummings

Co-PI: Laura Goodman, Sara Childs-Sanford

DESCRIPTION (provided by applicant): 

Salmonella enterica and Listeria monocytogenes are important causes of disease in domestic animals and humans, yet their epidemiology and clinical implications among wildlife have been poorly defined. Similarly, despite the escalation of antimicrobial resistance (AMR) to a public health crisis of global scale, factors that may contribute to the emergence of AMR in wildlife are largely unknown. Our overarching objective is to address these critical knowledge gaps using molecular epidemiologic approaches, through the following specific aims: (1) Determine the epidemiologic and clinical features of Salmonella and Listeria across wildlife species; (2) Characterize the Salmonella and Listeria isolates to ascertain potential public health risk; and (3) Identify the effects of antimicrobial administration on emergence of antimicrobial resistance in wildlife. Cornell University’s Janet L. Swanson Wildlife Hospital (WH) receives approximately 1,400 patients yearly (70% avian species, 25% mammals, and 5% reptiles and amphibians). This population constitutes a unique resource to achieve our research goals. Voided fecal samples (birds and mammals) or cloacal swab samples (reptiles and amphibians) will be collected from patients admitted to the WH over a 1-year duration. Salmonella and Listeria will be identified using established bacteriologic methods, and confirmed isolates will be characterized through whole-genome sequencing (WGS). Among a subset of patients receiving long-term antimicrobial therapy, samples will be collected weekly for analysis using a targeted sequencing-based panel that identifies nearly 500 AMR genes. Preliminary data demonstrate the impact of the proposed work. Five patients have been confirmed positive for Salmonella (1.5%; 5/338), and isolates thus far have been very closely related to human clinical isolates in the NCBI database. AMR has been identified, with several isolates demonstrating phenotypic resistance to azithromycin, cefoxitin, gentamicin, and streptomycin. Listeria monocytogenes has been isolated from 6.9% (23/335) of patients, including birds, mammals, and reptiles. Some of the Listeria monocytogenes isolates are genetically similar to other isolates (including human clinical isolates) in the NCBI database, and two avian isolates show evidence of hyper-virulence.