Retrospective Analysis of Multisite versus Single Site Blood Cultures in Neonatal Foals

Abstract:

Background: Sepsis is a detrimental disease in neonatal foals. Due to changes in hemodynamic status in critical foals, single-site and time-point blood culture (BC) as performed are likely to contribute to the poor yield of BC. Hypothesis: We hypothesize that obtaining blood cultures from multiple sites will improve identification of sepsis. Animals: Records from 104 foals ( < 14 days old) presenting to tertiary referral centers with BC obtained on admission were reviewed.

Methods: A retrospective review to compile BC results from sites collected (jugular and peripheral veins), clinical information, and sepsis scoring (SS) of the foals. Chi-squared analysis was performed to assess BC sites collected, and t-test for analysis of SS across the populations.

Results: Of the 104 foals 57 were bacteremic, 59% with single-site and 53% with two-site BC (P>0.05). Isolates varied with the most common being Staphylococcus spp. (n=13), Actinobacillus spp. (n=9), Escherichia coli (n=7), and Bacillus spp. (n=6). Three foals with single-site and seven foals with two-site BC yielded only minor bacterial species often considered contaminants. The foals with minor species identified on two-site BC had significantly greater SS of 12.7(+/- 2.69) compared to those with single-site 6.7(+/- 3.21) (P=0.015). Two of the single-site and all seven with two-site BC were suspected septic on clinical examination.

Conclusions: Larger case numbers are needed to determine whether sampling of multiple sites is a preferred method of obtaining BC to improve identification of sepsis in foals. Minor or commensal bacteria identified might be significant sources of infection or indications of sepsis.