Hallowell KL, Hepworth-Warren KL, Dembek K. An updated description of bacterial pneumonia in adult horses and factors associated with death.
J Vet Intern Med 2024. [PMID:
39005215 DOI:
10.1111/jvim.17141]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2024] [Accepted: 06/18/2024] [Indexed: 07/16/2024] Open
Abstract
BACKGROUND
Available descriptive studies on equine pneumonia are outdated or focus on specific horse or bacterial populations.
OBJECTIVES
To describe the clinical presentation and bacterial isolates of adult horses with bacterial pneumonia and identify factors associated with death.
ANIMALS
One hundred sixteen horses >2 years old with bacterial pneumonia.
METHODS
Retrospective case series. Data regarding history, physical examination, clinicopathologic features, treatment, bacterial culture and sensitivity, and outcome were collected and analyzed retrospectively.
RESULTS
Historical risk factors were present for 60% of cases, whereas abnormal vital signs on intake were present for <50%. Most horses (58%) underwent at least 1 change of antimicrobial treatment, and 67% received the highest-priority critically important antimicrobials. Streptococcus zooepidemicus was the most isolated bacteria (44%), followed by Escherichia coli (19%), Klebsiella spp. (18%), other Streptococcus species (17%), and Bacillus spp. (13%). Fusobacterium spp. were the most common anaerobic isolates (11%). Antimicrobial susceptibility varied widely. Survival to discharge was 73%. Heart rate at presentation (odds ratio [OR] 1.08, 95% confidence interval [CI] 1.008-1.17, P = .03) and higher creatinine (OR 14.1, 95% CI 1.56-127.6, P = .02) increased the risk of death. Higher lymphocyte count (OR 0.27, 95% CI 0.08-0.94, P = .04) reduced risk.
CONCLUSIONS AND CLINICAL IMPORTANCE
Contrasting older literature, Fusobacterium spp. were the most common anaerobes. Streptococcus zooepidemicus remained the most common isolate and was predictably susceptible to penicillin. Antimicrobial susceptibility was otherwise variable and broad applicability is limited as this was a single-center study. Increased risk of death associated with tachycardia and abnormally high serum creatinine concentration is consistent with previous studies.
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