In vitro and in vivo antibiofilm activity of a coral associated actinomycete against drug resistant Staphylococcus aureus biofilms

Staphylococcus aureus is now amongst the most important pathogenic bacteria responsible for bloodstream nosocomial infections and for biofilm formation on indwelling medical devices. Its increasing resistance to common antibiotics, partly attributed to its ability to form biofilms, is a challenge for the development of new antimicrobial agents. Accordingly, the goal of this study was to evaluate the effect of a coral associated actinomycete (CAA) - 3 on S. aureus biofilms both in vitro and in vivo. Methanolic extracts of CAA-3 showed a reduction in in vitro biofilm formation by S. aureus ATCC 11632, methicillin resistant S. aureus ATCC 33591 and clinical isolates of S. aureus at the biofilm inhibitory concentration (BIC) of 0.1 mg ml(-1). Furthermore, confocal laser scanning microscope (CLSM) studies provide evidence of CAA-3 inhibiting intestinal colonisation of S. aureus in the nematode Caenorhabditis elegans. To conclude, this study for the first time, reports CAA as a promising source of anti-biofilm compounds, for developing novel drugs against highly resistant staphylococcal biofilms.