A heterodimer comprised of two bovine lactoferrin antimicrobial peptides exhibits powerful bactericidal activity against Burkholderia pseudomallei

Melioidosis is a severe infectious disease that is endemic in Southeast Asia and Northern Australia. Burkholderia pseudomallei, the causative agent of this disease, has developed resistance to an increasing list of antibiotics, demanding a search for novel agents. Lactoferricin and lactoferrampin are two antimicrobial domains of lactoferrin with a broad spectrum of antimicrobial activity. A hybrid peptide (LFchimera) containing lactoferrampin (LFampin265-284) and a part of lactoferricin (LFcin17-30) has strikingly higher antimicrobial activities compared to the individual peptides. In this study, the antimicrobial activities of this chimeric construct (LFchimera1), as well as of another one containing LFcin17-30 and LFampin268-284, a shorter fragment of LFampin265-284 (LFchimera2), and the constituent peptides were tested against 7 isolates of B. pseudomallei and compared to the preferential antibiotic ceftazidime (CAZ). All isolates including B. pseudomallei 979b shown to be resistant to CAZ, at a density of 105 CFU/ml, could be killed by 5-10 μM of LFchimera1 within 2 h, while the other peptides as well as the antibiotic CAZ only inhibited the B. pseudomallei strains resulting in an overgrowth in 24 h. These data indicate that LFchimera1 could be considered for development of therapeutic agents against B. pseudomallei