Klebsiella pneumoniae Complex-Associated Peritonitis, Lymphadenitis, and Pyelonephritis in Juvenile Raccoons (Procyon lotor) under Rehabilitator Care in New York, New Jersey, and Wisconsin, USA

Klebsiella spp. are gram-negative facultative anaerobic heavily encapsulated bacteria associated with opportunistic and primary infections in a wide range of species. We assessed a series of cases (n=8) of necrosuppurative peritonitis, lymphadenitis, and/or pyelonephritis in wild juvenile raccoons (Procyon lotor) that died under rehabilitator care in New York, New Jersey, and Wisconsin, US, between July 2020 and December 2023, plus a retrospective case of a juvenile raccoon necropsied from New York in August 2011. Gross necropsy (n=9) and histopathology (n=9) were performed to characterize the lesions, whereas bacterial culture (n=8) was used to identify and characterize the bacteria and associated phenotype. We observed gram-negative short rods and coccobacilli (7/9; 78%), fibrinosuppurative peritonitis of variable severity (7/9; 78%) correlated to gross pyoabdomen (5/9; 56%) or abscessation (2/9; 22%), lymphadenomegaly and associated necrosuppurative lymphadenitis (5/9; 56%), and urinary tract disease (3/9; 33%). Aerobic culture of affected tissues isolated Klebsiella pneumoniae (n=4), K. pneumoniae subsp. ozaenae (n=2), Klebsiella variicola (n=1), and Klebsiella sp. (n=1). Our study strongly suggests an association of bacteria within the K. pneumoniae complex with peritonitis, lymphadenitis, and pyelonephritis in raccoons. Disease might be associated with underlying nosocomial infection given that all animals were under rehabilitator care at the time of death.