Therapy of suspected septicemia in neonatal foals using plasma-containing antibodies to core lipopolysaccharide (LPS).

Equine antiserum to core lipopolysaccharide (LPS) was evaluated in a double-blind prospective study for therapeutic benefit in suspected septicemia in neonatal foals. Forty foals younger than 7 days of age were included in the study by satisfaction of clinical and laboratory criteria, suggestive of gram-negative septicemia. Twenty-two foals were treated with core LPS antiserum (plasma produced from horses which were hyperimmunized with rough gram-negative mutant bacterin) and 18 foals received "nonimmune" plasma (from horses prior to immunization against core LPS). All foals received antimicrobials, fluids, and other supportive care measures, depending on clinical signs and according to accepted current practice. The clinical and laboratory data of each foal were monitored and recorded daily for 14 days after plasma treatment or until death. The overall survival rate of these 40 foals with septicemia was 52.5%. The most prevalent diagnoses in addition to septicemia were enteritis and pneumonia. Of 30 positive bacterial cultures, 93% were due to gram-negative organisms. There was no statistically significant increase in survival rate in the 22 foals given core LPS antiserum (P greater than 0.05).