Antibiograms of field and hospital acquired equine neonatal bacterial fluid cultures in the Midwestern United States: 149 samples (2007-2018).
Authors: Bookbinder Lauren C, Mani Rinosh, Carr Elizabeth A
Journal: Journal of veterinary internal medicine
Summary
# Editorial Summary: Antibiogram trends in equine neonatal infections Establishing current antibiotic susceptibility patterns for neonatal equine pathogens is crucial for selecting effective empirical therapy, particularly as resistance profiles shift over time and between geographic regions. This retrospective analysis examined 149 fluid samples from 133 foals under 30 days old submitted for bacterial culture across the Midwestern United States between 2007 and 2018, reviewing culture results, antimicrobial susceptibilities, treatment protocols, and clinical outcomes. Gram-positive organisms predominated amongst the 90 isolates identified (56%), with anaerobes representing a notably higher proportion than previously documented, yet encouragingly over 70% of aerobic isolates remained susceptible to ampicillin, ceftiofur, chloramphenicol, trimethoprim-sulphamethoxazole, and standard penicillin-aminoglycoside combinations. Overall survival reached 77% of foals, with negative fluid culture proving the strongest prognostic indicator; notably, specific empirical antibiotic choices did not significantly influence outcomes, suggesting that rapid diagnosis and aggressive supportive care may supersede drug selection in determining survival. These findings validate continued use of traditional empirical protocols in the Midwest whilst highlighting the need for regular local surveillance, as the shift towards increased gram-positive and anaerobic prevalence may reflect changing nosocomial patterns that differ from other geographic regions.
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Practical Takeaways
- •Current empirical antimicrobial protocols for neonatal sepsis in the Midwest remain effective based on local antibiogram data; ampicillin, ceftiofur, and chloramphenicol combinations show good coverage
- •Negative fluid culture is the strongest predictor of survival—focus diagnostic and treatment efforts on identifying and managing infection status early
- •Monitor regional trends in gram-positive and anaerobic pathogen prevalence; if resistance patterns shift in your area, request updated local antibiogram data to guide empirical therapy
Key Findings
- •Gram-positive organisms predominated in 56% (50/90) of isolates, exceeding previous reports
- •Greater than 70% of aerobic isolates were susceptible to ampicillin, ceftiofur, chloramphenicol, and trimethoprim/sulfamethoxazole
- •77% of foals (81/105) survived, with survival associated with negative fluid culture but not empirical antimicrobial choice
- •Anaerobic isolates were more common than previously reported in equine neonatal infections