Ctriporin, a new anti-methicillin-resistant Staphylococcus aureus peptide from the venom of the scorpion Chaerilus tricostatus.

Antibiotic-resistant microbes, such as methicillin-resistant Staphylococcus aureus, seriously threaten human health. The outbreak of "superbugs" in recent years emphasizes once again the need for the development of new antimicrobial agents or resources. Antimicrobial peptides have an evident bactericidal effect against multidrug-resistant pathogens. In the present study, a new antimicrobial peptide, ctriporin, was cloned and characterized from the venom of the scorpion Chaerilus tricostatus, an animal which has not yet been explored for toxic peptide resources. The MICs of ctriporin against Staphylococcus aureus, Bacillus thuringiensis, Bacillus subtilis, Micrococcus luteus, and Candida albicans are 5 to 20 μg/ml. Meanwhile, it MIC against clinical antibiotic-resistant bacterial strains is 10 μg/ml. Furthermore, the potential for ctriporin to be used as a topical antibiotic for treating staphylococcal skin infections was investigated. External use of the peptide ctriporin dramatically decreased the bacterial counts and cured skin infections in mice. In addition, ctriporin demonstrates antimicrobial efficacy via the bactericidal mechanism of rapid cell lysis. Together, these results suggest the potential of developing ctriporin as a new topical antibiotic.