Biofilm Eradication and Bactericidal Activity of the Red Sea Sponge Acarnus Wolffgangi against MRSA and Other Skin Pathogen

The escalating threat of antibiotic-resistant Gram-positive bacteria, such as Staphylococcus aureus (including MRSA) and Streptococcus pyogenes , necessitates the discovery of novel antimicrobial agents. Marine sponges, particularly from the biodiverse Red Sea, are promising sources of bioactive secondary metabolites. This study investigates the antibacterial and antibiofilm properties of organic extracts from two under-explored Red Sea demosponges, Acarnus wolffgangi and Dragmacidon durissimum , against skin infection-causing Gram-positive and Gram-negative pathogens. Extracts were obtained using methanol-dichloromethane and tested via agar well diffusion, broth microdilution, and biofilm assays. Acarnus wolffgangi exhibited significant antibacterial activity against S. aureus , MRSA, and S. epidermidis , with MIC values as low as 125 µg/mL and MBC values of 500 µg/mL, alongside notable biofilm inhibition and eradication at sub-MIC concentrations. In contrast, Dragmacidon durissimum showed no significant activity. Scanning electron microscopy revealed bacterial cell wall disruption by A. wolffgangi extracts, suggesting a bactericidal mechanism. High-performance liquid chromatography confirmed the presence of gallic acid (10 µg/mL) in both extracts. These findings highlight A. wolffgangi as a potential source of novel antimicrobial agents to combat resistant Gram-positive pathogens, underscoring the therapeutic potential of Red Sea sponges. Further research is needed to isolate and characterize active compounds for clinical development.