Antibiotic properties of bovine lactoferrin on Helicobacter pylori

To investigate a potential new treatment for gastric Helicobacter pylori in fection, we have examined the use of the natural antibiotic lactoferrin, fo und in bovine milk, for activity against Helicobacter species both in vitro and in vivo. Lactoferrin was bacteriostatic to H. pylori when cultured at concentrations greater than or equal to 0.5 mg/ml. Growth of H. pylori was not inhibited by another milk constituent, lysozyme, or by a metabolite of lactoferrin, lactoferricin B, but growth was inhibited by the iron chelator deferoxamine mesylate. Lactoferrin inhibition of growth could be reversed by addition of excess iron to the medium. Lactoferrin in retail dairy milk was found to be more stable intragastrically than unbuffered, purified lact oferrin. Treatment of H. felis-infected mice with lactoferrin partially rev ersed mucosal disease manifestations, It is concluded that bovine lactoferr in has significant antimicrobial activity against Helicobacter species ill vitro and in vivo. Bovine lactoferrin should be further investigated for po ssible use in H. pylori infections in man.