Equine blood cultures: Can we do better?
Authors: Giancola Shyla, Hart Kelsey A
Journal: Equine veterinary journal
Summary
Blood culture remains the definitive diagnostic tool for confirming bacteraemia in septic horses and foals, yet culture failure and contamination frequently compromise its clinical utility in equine practice, often resulting in missed diagnoses or inappropriate antimicrobial selection. Giancola and Hart's 2023 review synthesised current evidence on methodological variables affecting equine blood culture accuracy, examining collection techniques (aseptic protocol, sample volume, anatomical site, timing and frequency), laboratory processing methods, and patient factors including infection location and regional microbial populations. Key findings emphasise that no standardised approach currently exists for equine blood culture—a critical gap given that false negatives or false positives directly drive unnecessary antimicrobial use, antibiotic resistance development, and poorer patient outcomes. The authors identified several optimisable parameters: optimal blood volume for culture, ideal collection sites, and evidence-based sampling timing and frequency remain poorly defined in the equine literature, particularly for neonatal foals with suspected sepsis. For practitioners, this underscores the importance of meticulous aseptic technique, appropriate sample volume, and potentially multiple collection attempts when sepsis is suspected; however, standardised protocols informed by targeted research are urgently needed to improve the reliability of blood culture as a diagnostic tool and reduce antimicrobial resistance in equine populations.
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Practical Takeaways
- •Standardize your blood culture collection technique by optimizing aseptic procedure, collection site, blood volume, and sampling frequency to improve diagnostic accuracy in suspected septic cases
- •Recognize that negative blood cultures do not exclude bacterial sepsis in horses and foals—clinical signs must guide antimicrobial therapy decisions while awaiting culture results
- •Work with your laboratory to understand their specific collection requirements and optimize sample handling to reduce contamination and improve pathogen recovery rates
Key Findings
- •Blood culture methodology in equine medicine lacks standardization, affecting accuracy of results for detecting bacteraemia in septic horses and foals
- •Multiple variables including blood volume collected, aseptic technique, collection site, timing, and frequency substantially impact yield and contamination rates of blood cultures
- •Patient-specific and environmental factors such as husbandry, primary infection site, and geographic location influence blood culture results and microbial identification
- •Inaccurate blood culture results can lead to inappropriate antimicrobial use, resulting in poor patient outcomes and contributing to antimicrobial resistance development