Pneumonia Caused by Klebsiella spp. in 46 Horses.
BACKGROUND
Klebsiella spp. are implicated as a common cause of bacterial pneumonia in horses, but few reports describe clinical presentation and disease progression.


OBJECTIVE
To describe the signalment, clinicopathologic data, radiographic and ultrasonographic findings, antimicrobial susceptibility, outcome, and pathologic lesions associated with Klebsiella spp. pneumonia in horses.


METHODS
Forty-six horses from which Klebsiella spp. was isolated from the lower respiratory tract.


METHODS
Retrospective study. Medical records from 1993 to 2013 at the William R. Pritchard Veterinary Medical Teaching Hospital, University of California, Davis were reviewed. Exact logistic regression was performed to determine if any variables were associated with survival to hospital discharge.


RESULTS
Survival in horses <1 year old was 73%. Overall survival in adults was 63%. For adults in which Klebsiella pneumoniae was the primary isolate, survival was 52%. Mechanical ventilation preceded development of pneumonia in 11 horses. Complications occurred in 25/46 horses, with thrombophlebitis and laminitis occurring most frequently. Multi-drug resistance was found in 47% of bacterial isolates. Variables that significantly impacted survival included hemorrhagic nasal discharge, laminitis, and thoracic radiographs with a sharp demarcation between marked caudal pulmonary alveolar infiltration and more normal-appearing caudodorsal lung.


CONCLUSIONS
Klebsiella spp. should be considered as a differential diagnosis for horses presenting with hemorrhagic pneumonia and for horses developing pneumonia after mechanical ventilation. Multi-drug resistance is common. Prognosis for survival generally is fair, but is guarded for adult horses in which K. pneumoniae is isolated as the primary organism.
William R. Pritchard Veterinary Medical Teaching Hospital, University of California, Davis, CA.
K E
KE
Estell
William R. Pritchard Veterinary Medical Teaching Hospital, University of California, Davis, CA.
A
A
Young
William R. Pritchard Veterinary Medical Teaching Hospital, University of California, Davis, CA.
T
T
Kozikowski
William R. Pritchard Veterinary Medical Teaching Hospital, University of California, Davis, CA.
E A
EA
Swain
Department of Pathology, Microbiology, and Immunology, School of Veterinary Medicine, University of California, Davis, CA.
B A
BA
Byrne
Department of Pathology, Microbiology, and Immunology, School of Veterinary Medicine, University of California, Davis, CA.
C M
CM
Reilly
Department of Population Health and Reproduction, School of Veterinary Medicine, University of California, Davis, CA.
P H
PH
Kass
Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, CA.
M
M
Aleman
D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology / Q000627:therapeutic use; D024901:Drug Resistance, Multiple, Bacterial; D006734:Horse Diseases / Q000382:microbiology*; D006736:Horses; D007709:Klebsiella / Q000187:drug effects / Q000302:isolation & purification*; D007710:Klebsiella Infections / Q000382:microbiology / Q000473:pathology / Q000662:veterinary*; D018410:Pneumonia, Bacterial / Q000382:microbiology / Q000517:prevention & control / Q000662:veterinary*; D012189:Retrospective Studies
D000900:Anti-Bacterial Agents
Hemorrhagic pneumonia; Multi-drug resistance; Respiratory infection