Initial antimicrobial treatment of foals with sepsis: Do our choices make a difference?
Authors: Theelen Mathijs J P, Wilson W David, Byrne Barbara A, Edman Judy M, Kass Philip H, Magdesian K Gary
Journal: Veterinary journal (London, England : 1997)
Summary
# Editorial Summary: Antimicrobial Selection in Neonatal Foal Sepsis Selecting appropriate initial antimicrobial therapy for septic foals is challenging when culture results are unavailable, yet the choice substantially impacts survival outcomes. Researchers at UC Davis retrospectively analysed 213 septic foals (≤30 days old) with confirmed bacterial isolates from sterile sites, performing susceptibility testing on 306 bacterial isolates and comparing survival rates between foals whose initial treatment covered all isolated organisms versus those with resistant pathogens present. Foals receiving antimicrobials to which all their bacterial isolates were susceptible achieved a 65.4% survival rate, compared with only 41.7% survival when one or more resistant organisms were present—a clinically meaningful difference despite wide confidence intervals reflecting the small resistant group. The findings validate amikacin combined with ampicillin as a rational empirical choice for neonatal sepsis, supporting current clinical protocols, though practitioners should recognise that even optimal initial coverage leaves considerable room for improvement through supportive care optimisation and early diagnosis. Given the high prevalence of multi-resistant pathogens in hospital settings, obtaining blood cultures on admission and adjusting therapy based on susceptibility results remains critical for maximising outcomes in this high-risk population.
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Practical Takeaways
- •When treating neonatal foal sepsis, using amikacin + ampicillin as initial therapy is still evidence-supported, though outcomes are significantly better when bacterial susceptibilities confirm these choices
- •Culture and susceptibility testing should be prioritized in septic foals, as antimicrobial resistance substantially reduces survival odds (from 65% to 42%)
- •Even with appropriate initial antimicrobial selection, expect ~35% mortality in treated foals; resistance dramatically worsens prognosis
Key Findings
- •Foals with all bacteria susceptible to initial antimicrobial treatment had 65.4% survival rate compared to 41.7% when one or more isolates were resistant (RR 1.57)
- •Study included 213 foals and 306 bacterial isolates with susceptibility testing performed using broth microdilution
- •Amikacin combined with ampicillin remains appropriate for initial empirical treatment of septic foals despite lack of statistical significance in this cohort