Comparative activities of polycationic peptides and clinically used antimicrobial agents against multidrug-resistant nosocomial isolates of Acinetobacter baumannii

The in vitro activity of buforin II, cecropin P1, indolicidin, magainin II and ranalexin, alone and in combination with eight clinically used antimicr obial agents was investigated against 12 multidrug-resistant strains of Aci netobacter baumannii isolated from immunocompromised patients, Antimicrobia l activities were measured by MIG, MBC and viable count, The peptides had a varied range of inhibitory values: overall, the organisms were more suscep tible to buforin II (MIC range 0.25-16 mg/L), cecropin P1 (0.50-32 mg/L) an d magainin II (0.50-16 mg/L), Synergy occurred when magainin II was combine d with p-lactam antibiotics.