In a research project done at UC Davis, the results of 213 cases of foal sepsis were evaluated. Foals included in this study were less than 30 days of age, and sepsis (the presence of bacteria in the bloodstream) was confirmed by cultures of the blood or samples collected from other sites in their body.
Because foal sepsis is a rapidly progressive disease that requires the immediate use of antibiotics, oftentimes veterinarians do not know the exact bacteria responsible at the time that treatment must be started. Which antibiotic or antibiotic combination chosen is based on what the most likely bacteria would be that is causing the sepsis. A common antibiotic combination is that of amikacin and ampicillin, and this was found to be one of the most effective for the empirical treatment of foal sepsis in these foals less than 30 days of age.
In their study, the bacteria in 91.5% of the foals were susceptible to this combination. The researchers concluded that this combination “remains one of the most effective antimicrobial drug combinations to treat foals with sepsis and should be used as an initial treatment, assuming normal renal (kidney) function”.
Article: Theelen, MJP etc al. Cumulative Antimicrobial Susceptibility of Bacteria isolated from Foals with Sepsis: 1990-2015. AAEP Proc 2016, vol. 62, pp. 497-98.