Effect of bile on the action of blood against Salmonella.

Kaye, Donald (New York Hospital-Cornell Medical Center, New York, N.Y.), Michelle Palmieri, and Heonir Rocha. Effect of bile on the action of blood against Salmonella. J. Bacteriol. 91:945-952. 1966.-Bile is superior to Trypticase Soy Broth (BBL) as a medium for isolation of Salmonella from blood. In addition to inhibitory activity against many of the common bacterial contaminants, bile has the additional advantages of a greater frequency of isolation of Salmonella and more rapid isolation. This study investigated the factors responsible for the superiority of bile. A 20% dilution of normal human blood in Trypticase Soy Broth was usually inhibitory or bactericidal against strains of Salmonella. Similarly, a 20% dilution in Trypticase Soy Broth of serum from patients with Salmonella bacteremia was frequently inhibitory or bactericidal for the salmonellae isolated from their blood. Bile inactivated the bactericidal activity of blood or serum by inactivating complement activity. Bile (13%) in Trypticase Soy Broth inactivated complement activity in 33% blood or serum. Although bile has anticoagulant and hemolytic effects, no evidence was found that these activities contribute to the superiority of bile over Trypticase Soy Broth as a culture medium for Salmonella. No evidence was found for a growth-promoting factor in bile for Salmonella. Bile was much more effective than 0.5 or 2.0% sodium taurocholate broth in inactivating the bactericidal activity of blood.