Blood culture status in mature horses with diarrhoea: a possible association with survival.
Authors: Johns I, Tennent-Brown B, Schaer B Dallap, Southwood L, Boston R, Wilkins P
Journal: Equine veterinary journal
Summary
# Blood Culture Status in Mature Horses with Diarrhoea: Clinical Significance and Prognostic Value Bacteraemia has long been suspected as a complicating factor in equine diarrhoea cases, yet its true prevalence and clinical consequences remained poorly defined until this investigation. Researchers prospectively cultured blood from 31 mature horses at admission and 24 hours later, quantifying the incidence of positive cultures and correlating findings with survival outcomes and admission laboratory parameters. Nearly one-third of the cohort (29%) yielded positive blood cultures within 24 hours, with Corynebacterium spp. predominating; crucially, horses with positive blood cultures demonstrated significantly reduced survival rates. Clinical indicators of bacteraemia were evident on presentation: blood culture–positive horses exhibited elevated heart rates, packed cell volumes and plasma potassium concentrations compared to culture-negative animals, with the 24-hour samples revealing persistently elevated PCV alongside lower total plasma protein. For practitioners managing diarrhoea cases, these findings suggest that blood culture results—obtained as part of routine admission diagnostics—may provide valuable prognostic information to inform both treatment intensity and owner counselling, particularly when conventional clinical indicators prove ambiguous.
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Practical Takeaways
- •Blood culture results should be obtained at admission in horses presenting with diarrhoea, as positive cultures are more common than previously thought and significantly worsen prognosis
- •Elevated heart rate, elevated PCV, and high plasma potassium at admission may serve as clinical warning signs for bacteraemia in diarrheic horses and should prompt consideration of sepsis protocol
- •Positive blood culture status provides useful prognostic information for client counseling and treatment intensity decisions in diarrheic horses
Key Findings
- •29% (9/31) of mature horses with diarrhoea were blood culture positive within 24 hours of admission
- •Horses with positive blood cultures were significantly less likely to survive compared to culture-negative horses
- •Blood culture positive horses had significantly higher heart rate, packed cell volume, and plasma potassium at admission
- •Common isolates included Corynebacterium spp. (6 cases), Streptococcus spp. (2 cases), and other gram-positive and gram-negative organisms