antimicrobial and antibiofilm activity of human cationic antibacterial peptide (ll-37) and its analogs against pan-drug-resistant acinetobacter baumannii

Background: human cationic antibacterial peptide hcap18/ll-37 is the only known cathelicidin, which is part of the innate immune system of humans. the antimicrobial activity of ll-37 against multi-drug-resistant acinetobacter baumannii has been reported recently, however, whether ll-37 and its analogues (ll/cap18 and ff/cap18) have antimicrobial activity against pan-drug-resistant acinetobacter baumannii (pdrab) is still unknown. objectives: this study aims to clarify the antimicrobial activity of ll-37 and its analogues against pdrab. methods: in this study, we evaluated ll-37 and its truncated analogs inhibitory effect on the growth of pdrab by minimum inhibitory concentration (mic) and minimum bactericidal concentration (mbc) analysis, we also examined the effect of ll-37 and its analogs on bacterial biofilm formation by using a quantitative crystal violet assay. results: ll-37 and its truncated analogs were effective in inhibiting the growth of pdrab and had a rapid killing ability. after exposure to the peptides, the development of the pdrab biofilm was inhibited. strong inhibitory and dispersion effects of ff/cap18 on the biofilm were confirmed by fluorescence microscopy and field emission scanning electron microscopy. conclusions: this results show that ff/cap18 is a potential antimicrobial agent for treating pan-drug–resistant bacterial infections.