The predictive ability of blood-based biomarkers to detect bacteremia in hospitalized neonatal foals.
Authors: Samuels Amanda N, Collins Niamh M, Hanlon Kelly, Bartish Celine, Kelly Payton, Kamr Ahmed M, Toribio Ramiro E
Journal: Veterinary journal (London, England : 1997)
Summary
Early detection of septicaemia in hospitalised neonatal foals remains clinically challenging, yet survival improves substantially with prompt identification and intervention; this study investigated whether blood-based biomarkers commonly used in human medicine—specifically neutrophil-to-lymphocyte ratio (NLR), neutrophil-to-monocyte ratio (NMR), monocyte-to-lymphocyte ratio (MLR), and cell-free DNA (cfDNA)—could enhance diagnostic accuracy in foals under five days old. Researchers analysed 391 hospitalised foals with complete blood counts and blood cultures taken at admission, building logistic regression models that incorporated physical examination findings, white blood cell counts, immunoglobulin G (IgG) levels, and cfDNA measurements to predict positive blood culture results and identify the type of bacteraemia present. A composite model combining cfDNA, IgG, NLR, and WBC demonstrated excellent predictive ability for detecting any bacteraemia (AUC = 0.806), whilst cfDNA, IgG, and neutrophil counts independently predicted Gram-negative infection (AUC = 0.807); monocyte count and age predicted Gram-positive bacteraemia less reliably (AUC = 0.67), and notably, NMR and MLR showed no significant difference between infected and non-infected foals. For equine practitioners, these findings suggest that measuring plasma cfDNA alongside routine haematology and IgG levels could substantially improve early identification of bacteraemia in at-risk neonates, potentially enabling targeted antimicrobial therapy and reducing mortality, though the technique's availability and cost-effectiveness in clinical practice warrant consideration.
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Practical Takeaways
- •Blood-based biomarker panels combining cfDNA, IgG, NLR, and WBC can help identify neonatal foals with bacteremia early, enabling faster treatment decisions in critical cases
- •cfDNA and neutrophil counts may help distinguish Gram-negative from Gram-positive infections, potentially guiding antimicrobial selection while awaiting culture results
- •NLR is a practical readily-available marker from routine bloodwork that shows promise in bacteremia detection, whereas NMR and MLR do not add diagnostic value
Key Findings
- •Plasma cfDNA, IgG, NLR, and WBC were independent predictors of bacteremia with composite model AUC of 0.806
- •Plasma cfDNA, IgG, and neutrophil counts independently predicted Gram-negative bacteremia (AUC = 0.807)
- •Monocyte count and age predicted Gram-positive bacteremia with fair discrimination (AUC = 0.67)
- •NLR and plasma cfDNA were significantly altered in bacteremic foals, while NMR and MLR showed no significant differences