Bacterial isolates from blood and their susceptibility patterns in critically ill foals: 543 cases (1991-1998)

J Am Vet Med Assoc. 2001 May 15;218(10):1608-10. doi: 10.2460/javma.2001.218.1608.


Objective: To assess microorganisms isolated from blood specimens obtained from critically ill neonatal foals and to evaluate their antimicrobial susceptibility patterns.

Design: Retrospective study.

Animals: 543 neonatal foals.

Procedure: Medical records of foals that were < 1 month old and were admitted to a referral neonatal intensive care unit were reviewed for results of bacteriologic culture of blood and antimicrobial susceptibility patterns.

Results: At least 1 microorganism was isolated from 155 of 543 (28.5%) foals. Escherichia coli was the most commonly isolated bacterium. A single gram-positive organism was detected in 49 foals. Although 90% of the E coli isolates were susceptible to amikacin, some gram-negative and gram-positive organisms had resistance against multiple antimicrobials.

Conclusions and clinical relevance: Gram-negative bacteria remain the most common isolates from blood of neonatal foals; however, gram-positive organisms were also found, and with greater prevalence than reported elsewhere. Susceptibility patterns may vary, and resistance to multiple antimicrobials may develop. This is especially true for organisms such as Enterobacter spp and Enterococcus spp. Prudent empirical treatment for neonatal sepsis should include broad-spectrum antimicrobials.

Publication types

  • Case Reports

MeSH terms

  • Animals
  • Animals, Newborn
  • Drug Resistance, Bacterial
  • Drug Resistance, Multiple, Bacterial
  • Escherichia coli / drug effects
  • Escherichia coli / isolation & purification
  • Escherichia coli Infections / microbiology
  • Escherichia coli Infections / veterinary
  • Female
  • Gram-Negative Bacteria / drug effects*
  • Gram-Positive Bacteria / drug effects*
  • Horse Diseases / microbiology*
  • Horses
  • Male
  • Retrospective Studies
  • Sepsis / microbiology
  • Sepsis / veterinary*