Actinobacillus sp. Bacteremia in Foals : clinical signs and prognosis

Abstract

Medical records of 101 blood culture-confirmed bacteremic foals were reviewed to determine whether foals with Actinobacillus sp. bacteremia are affected at an earlier age, have more severe signs of disease, and have a worse prognosis than do foals with bacteremia of other causes. Thirty percent (30/101) of bacteremic foals had Actinobacillus sp. cultured, and these were 2 times more likely to die (crude odds ratio [ORCR] 0.8, 4; P 5 .14), with a survival rate of 43% (13/30) compared to the overall survival rate of 55% (56/101). When compared to other bacteremic foals, foals with actinobacillosis were 7 times more likely to have been sick from birth (adjusted odds ratio [ORADJ] 2, 26; P 5 .003) and 6 times more likely to have diarrhea (ORADJ 1, 22; P 5 .009). By bivariate analysis, foals with Actinobacillus sp. bacteremia were 5 times more likely to have a sepsis score .11 (ORCR 1, 18; P 5 .007), 6 times more likely to be obtunded (ORCR 2, 20; P 5 .005), and 3 times more likely to have pneumonia (ORCR 1, 7; P 5 .03). Furthermore, Actinobacillus sp. bacteremic foals were 27 times more likely to have a segmented neutrophil count ,3.3 3 109 cells/L (ORADJ 4, 166; P , .0001) and were 4.5 times more likely to have a band neutrophil count .0.46 3 109 cells/L (ORADJ 1, 17; P 5 .02) when compared to foals that had bacteremia caused by either gram-negative enteric or gram-positive organisms. Sepsis score was #11 in 49% (29/59) of bacteremia foals aged ,13 days for which a discernible sepsis score was calculable. Results of this study should improve the diagnostic sensitivity of clinical examinations of neonatal foals, thereby facilitating treatment decisions