Efficacy of chelerythrine against dual-species biofilms of Staphylococcus aureus and Staphylococcus lugdunensis.

Abstract

Staphylococcus aureus and Staphylococcus lugdunensis are often associated with pathogenic biofilms ranging from superficial mucosal to life-threatening systemic infections. Recent studies have reported that chelerythrine (CHE) displays antimicrobial activities against a few microorganisms, but its effects on dual-species biofilms of S. aureus and S. lugdunensis have never been reported. The purpose of this study was to investigate how dual-species biofilms of S. aureus and S. lugdunensis respond when challenged with CHE. Minimum inhibitory concentration (MIC) of CHE against planktic cells in dual-species culture was 8μg/mL. CHE also suppressed dual-species biofilm formation at minimal biofilm inhibitory concentration (MBIC90, 4μg/mL). Further, confocal laser scanning microscope (CLSM) using five fluorescent dyes revealed the dose-dependent reduction of the levels of three key biofilm matrix components, and reduced tolerance to gatifloxacin, of biofilms exposed to CHE. Moreover, CHE efficiently eradicated preformed dual-species biofilms at minimal biofilm eradication concentration (MBEC, 256μg/mL). Hence, CHE has the potential to address biofilm infections of clinical course and other biofilm-related diseases caused by S. aureus and S. lugdunensis.