CLINICAL AND MICROBIOLOGICAL CHARACTERIZATION OF LYMPH NODE ABSCESSATION IN PUP AND YEARLING CALIFORNIA SEA LIONS () UNDERGOING REHABILITATION IN A MARINE MAMMAL CENTER.

Severe focal to multifocal abscessation of the axillary and inguinal lymph nodes is an important cause of morbidity and mortality in stranded pup and yearling California sea lions (; CSLs) at The Marine Mammal Center (TMMC). A retrospective case review was conducted of all pup and yearling CSLs with axillary and/or inguinal lymph node abscesses admitted to this California rehabilitation center between January 2015 and December 2019 ( = 162). Clinical data and cultured isolates were evaluated to (1) characterize the clinical syndrome, (2) report isolated pathogens, and (3) investigate factors associated with clinical outcome (survival to release versus death). Of the 162 CSLs admitted with at least one axillary or inguinal lymph node abscess, almost all were in poor body condition, and overall mortality rate was 63% (102 of 165). Mortality rate was lower for animals presenting with a single abscess and abscess(es) in the inguinal location only; odds of death were significantly lower for animals that had their abscesses surgically drained ( = 0.029) and those that received antimicrobials ( = 0.037). Hematology and serum chemistry parameters at the time of abscess diagnosis reflected inflammation and malnutrition. Radiographic findings associated with abscesses from 45 cases included soft tissue swelling ( = 40), intralesional gas ( = 19), and osteomyelitis ( = 3). Ninety bacterial isolates were recovered from aerobic ( = 48) and anaerobic cultures ( = 17), 48.9% of which were gram negative. The most common gram-negative organisms were ( = 15), spp. ( = 8), and ( = 7), and the most common gram-positive organisms were ( = 10) and spp. ( = 9). Management of lymph node abscesses via surgical drainage and multimodal systemic antimicrobial therapy with a broad-spectrum of activity may be considered to improve survival of these cases.