Lactoferricin, a new antimicrobial peptide.
Lactoferricin B (LF-B) is a peptide derived from acid-pepsin digestion of bovine lactoferrin, which has antimicrobial properties. In order to assess the antimicrobial spectrum of LF-B and its possible in vivo uses, the minimum inhibitory and microbicidal concentrations of pure lactoferricin B were determined for a range of bacterial species and under varying conditions of growth including growth phase and size of the inoculum, pH and ionic strength of the medium. Lactoferricin B was bactericidal against a wide range of bacteria and Candida albicans. Proteus spp., Pseudomonas cepacia and Serratia spp. were resistant. The bactericidal activity of LF-B was inhibited by increasing ionic strength and bacterial inoculum and at acid pH. The activity of lactoferricin B was completely inhibited by the addition of 5% whole cow's milk and was reduced in the presence of increasing concentrations of mucin. These results indicate the potential of LF-B to reduce the numbers of organisms in a simple medium, but raise doubts about its role in vivo because of its sensitivity to changes in physical variables. It may be that lactoferricin exerts a transient antimicrobial effect at mucosal surfaces.
Department of Microbiology, Bristol Royal Infirmary, UK.
E M
EM
Jones
A
A
Smart
G
G
Bloomberg
L
L
Burgess
M R
MR
Millar
D000818:Animals; D000900:Anti-Bacterial Agents; D000890:Anti-Infective Agents / Q000302:isolation & purification* / Q000494:pharmacology; D000935:Antifungal Agents / Q000302:isolation & purification* / Q000494:pharmacology; D001419:Bacteria / Q000187:drug effects; D002175:Candida / Q000187:drug effects; D002417:Cattle; D006863:Hydrogen-Ion Concentration; D007781:Lactoferrin / Q000031:analogs & derivatives* / Q000037:antagonists & inhibitors / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology; D008826:Microbial Sensitivity Tests; D008892:Milk; D010434:Pepsin A
D000900:Anti-Bacterial Agents; D000890:Anti-Infective Agents; D000935:Antifungal Agents; C082171:lactoferricin B; D007781:Lactoferrin; D010434:Pepsin A