Lactoferricin of bovine origin is more active than lactoferricins of human, murine and caprine origin

The antimicrobial peptide lactoferricin is generated by gastric pepsin clea vage of lactoferrin. We hale examined the antimicrobial activity of lactofe rricins derived from lactoferrin of human, murine, caprine and bovine origi n with minimal inhibitory concentration (MIC) and minimal bactericidal conc entration (MBC) against E. coli ATCC 25922 and S. aureus ATCC 25923, We fou nd that lactoferricin of bovine origin (Lf-cin B) was the most efficacious of the lactoferricins tested. By comparing the linear and cyclic Lf-cin B m e found the cyclic peptide to be the most active. Lactoferricin B was moder ately active against E, coli ATCC 25922 and S, aureus ATCC 25923, but had n o activity against P. mirabilis or Y. enterocolitica, Lf-cin B showed good activity against C. albicans, C. tropicalis and C. neoformans.