In Vitro Pharmacokinetics of LL-37 and Oncorhyncin II Combination Against Acinetobacter baumannii

Background: Multidrug-resistant (MDR) Acinetobacter baumannii is one of the most common nosocomial pathogens. Antimicrobial peptides (AMPs) have been introduced as a viable alternative to antibiotics in the treatment of MDR pathogens.Objectives: This study was designed to assess the in vitro pharmacokinetics of the combination of two potent AMPs, LL-37 and on-corhyncin II, against A. baumannii (ATCC19606).Methods: The synthesized genes of oncorhyncin II and LL-37 were introduced into Escherichia coli BL21 as the expression host. The minimum inhibitory concentration (MIC), time-kills, and growth kinetics of these peptides were used to evaluate their antimicro-bial efficiencies against A. baumannii (ATCC19606).Results: LL-37 and oncorhyncin II recombinant peptides showed MIC of 30.6 and 95.87 mu g/mL against A. baumannii, respectively. Additive action was confirmed by combining the generated AMPs at the checkerboard approach. The combination of LL-37 and oncorhyncin II at 2 x MIC resulted in a rapid drop in log10 CFU/mL of A. baumannii in the time-kill and growth kinetic findings studies.Conclusions: The combination of the produced LL-37 and oncorhyncin II synergizes the bioactivity of the individual peptides. Therefore, these peptides or their combinations might function as novel antibiotics and be used to develop and produce new an-timicrobial drugs for the treatment of infections caused by A. baumannii.