ANTIBACTERIAL ACTIVITY OF LACTOFERRICIN, LYSOZYME AND EDTA AGAINST SALMONELLA-ENTERITIDIS

The antibacterial activity of a pepsin digest of bovine lactoferrin, c ontaining the peptide lactoferricin B against Salmonella enteritidis w as studied under various conditions. The digest had greater antibacter ial activity than lactoferrin in 1% peptone, was bactericidal and also increased the permeability of the outer membrane of the bacteria as d emonstrated by plating on bile salts agar. The antibacterial activity was inhibited in richer media, such as tryptic soy broth or milk-based or soy-based infant formula. Addition of lysozyme or EDTA or both, to the lactoferrin digest resulted in increased antibacterial activity o f the mixture. Lysosyme or EDTA alone had little or no activity agains t S. enteritidis. The increase in antibacterial activity obtained with the addition of lysozyme and EDTA to the lactoferrin digest was not s ufficient to overcome inhibition by components of the richer media.