ISOLATION AND CHARACTERIZATION OF A NOVEL MARINE BRUCELLA FROM A SOUTHERN SEA OTTER (ENHYDRA LUTRIS NEREIS), CALIFORNIA, USA.
We characterize Brucella infection in a wild southern sea otter ( Enhydra lutris nereis) with osteolytic lesions similar to those reported in other marine mammals and humans. This otter stranded twice along the central California coast, US over a 1-yr period and was handled extensively at two wildlife rehabilitation facilities, undergoing multiple surgeries and months of postsurgical care. Ultimately the otter was euthanized due to severe, progressive neurologic disease. Necropsy and postmortem radiographs revealed chronic, severe osteoarthritis spanning the proximal interphalangeal joint of the left hind fifth digit. Numerous coccobacilli within the joint were strongly positive on Brucella immunohistochemical labelling, and Brucella sp. was isolated in pure culture from this lesion. Sparse Brucella-immunopositive bacteria were also observed in the cytoplasm of a pulmonary vascular monocyte, and multifocal granulomas were observed in the spinal cord and liver on histopathology. Findings from biochemical characterization, 16S ribosomal DNA, and bp26 gene sequencing of the bacterial isolate were identical to those from marine-origin brucellae isolated from cetaceans and phocids. Although omp2a gene sequencing revealed 100% homology with marine Brucella spp. infecting pinnipeds, whales, and humans, omp2b gene sequences were identical only to pinniped-origin isolates. Multilocus sequence typing classified the sea otter isolate as ST26, a sequence type previously associated only with cetaceans. Our data suggest that the sea otter Brucella strain represents a novel marine lineage that is distinct from both Brucella pinnipedialis and Brucella ceti. Prior reports document the zoonotic potential of the marine brucellae. Isolation of Brucella sp. from a stranded sea otter highlights the importance of wearing personal protective equipment when handling sea otters and other marine mammals as part of wildlife conservation and rehabilitation efforts.
1   Marine Wildlife Veterinary Care and Research Center, California Department of Fish and Wildlife, Office of Spill Prevention and Response, 151 McAllister Way, Santa Cruz, California 95060, USA.|2   Karen C. Drayer Wildlife Health Center, School of Veterinary Medicine, University of California, One Shields Avenue, Davis, California 95616, USA.
Melissa A
MA
Miller
2   Karen C. Drayer Wildlife Health Center, School of Veterinary Medicine, University of California, One Shields Avenue, Davis, California 95616, USA.
Tristan L
TL
Burgess
1   Marine Wildlife Veterinary Care and Research Center, California Department of Fish and Wildlife, Office of Spill Prevention and Response, 151 McAllister Way, Santa Cruz, California 95060, USA.
Erin M
EM
Dodd
3   US Department of Agriculture, Animal and Plant Health Inspection Service, Veterinary Services, 4101 Laporte Avenue, Fort Collins, Colorado 80521, USA.
Jack C
JC
Rhyan
4   Department of Pathology, Microbiology and Immunology, University of California, One Shields Avenue, Davis, California 95616, USA.
Spencer S
SS
Jang
4   Department of Pathology, Microbiology and Immunology, University of California, One Shields Avenue, Davis, California 95616, USA.
Barbara A
BA
Byrne
5   The Marine Mammal Center, 2000 Bunker Road, Fort Cronkhite, Sausalito, California 94965, USA.
Frances M D
FM
Gulland
6   Monterey Bay Aquarium, 886 Cannery Row, Monterey, California 93940, USA.
Michael J
MJ
Murray
1   Marine Wildlife Veterinary Care and Research Center, California Department of Fish and Wildlife, Office of Spill Prevention and Response, 151 McAllister Way, Santa Cruz, California 95060, USA.
Sharon
S
Toy-Choutka
2   Karen C. Drayer Wildlife Health Center, School of Veterinary Medicine, University of California, One Shields Avenue, Davis, California 95616, USA.
Patricia A
PA
Conrad
5   The Marine Mammal Center, 2000 Bunker Road, Fort Cronkhite, Sausalito, California 94965, USA.
Cara L
CL
Field
7   University of New Hampshire, New Hampshire Veterinary Diagnostic Laboratory, 21 Botanical Lane, Durham, New Hampshire 03824, USA.
Inga F
IF
Sidor
2   Karen C. Drayer Wildlife Health Center, School of Veterinary Medicine, University of California, One Shields Avenue, Davis, California 95616, USA.
Woutrina A
WA
Smith
D000818:Animals; D000835:Animals, Wild; D002002:Brucella / Q000302:isolation & purification / Q000472:pathogenicity*; D002140:California; D010872:Caniformia; D010041:Otters / Q000382:microbiology*
Brucella; Enhydra lutris nereis; bp26; multilocus sequence typing; omp2; osteoarthritis; southern sea otter