The antimicrobial peptide BMAP-28 reduces lethality in mouse models of staphylococcal sepsis.

OBJECTIVE: A mouse model of staphylococcal sepsis was used to compare the efficacy of the bovine antimicrobial peptide BMAP-28, a compound of the cathelicidin family, with that of conventional antibiotics. DESIGN: Prospective, randomized, controlled animal study. SETTING: Research laboratory in a university hospital. SUBJECTS: BALB/c male mice. INTERVENTIONS: BALB/c mice were injected intravenously with 2.0 x 10(6) colony-forming units of live Staphylococcus aureus ATCC 25923 or with 5.0 x 10(8) heat-killed cells of the same strain. All animals were randomized to receive intravenously isotonic sodium chloride solution, 2 mg/kg BMAP-28, 7 mg/kg imipenem, 7 mg/kg vancomycin, 7 mg/kg clindamycin, and 7 mg/kg clarithromycin immediately and at 6 hrs after bacterial challenge. MEASUREMENTS AND MAIN RESULTS: Lethality, quantitative blood cultures, and detection of tumor necrosis factor-alpha and interleukin-6 plasma levels. In the experiments performed with live bacteria, all compounds reduced lethality rates and bacterial growth compared with controls. Imipenem and vancomycin exhibited the highest efficacy on these main outcome measures. In the experiments performed using heat-killed organisms, only BMAP-28 demonstrated significant efficacy on lethality rates, tumor necrosis factor-alpha, and interleukin-6 plasma levels compared with controls. CONCLUSION: These results highlight the capacity of BMAP-28 to reduce the effects of components of the bacterial cells and suggest that it may be beneficial in the treatment of severe staphylococcal infections in concert with other antimicrobial agents.