Antimicrobial Effects of Some Persian Gulf Marine Sponges

Background: We investigated in vitro antimicrobial activity of five marine sponge species collected from Kish Island in the Persian Gulf: Fascaplysinopsis reticulata , Callyspongia clavatus , Callyspongia siphonella , Niphates furcata , and Pseudosuberites clavatus against gram positive bacteria, gram negative bacteria, fungi and yeasts. Materials and Methods: Sponage extracts were prepared by two solvents of dichloromethane and methanol in three steps. The extracts were then tested with broth microdilution method. Results: Microorganisms varied in their susceptibility to extracts. Fungi were less sensitive than both gram-positive and gram-negative bacteria. Streptococcus pyogenes and Streptococcus mutans were more sensitive than other bacteria. All extracts showed acceptable antimicrobial activity against at least one bacterial strain. Marine sponge Fascaplysinopsis reticulata had the highest activity against all examined gram-positive bacteria including resistant strains (MIC of dichloromethane and methanolic extracts were in the range of 0.25-8 and 16-32 µg/ml, respectively). Conclusion: The results showed that marine sponge Fascaplysinopsis reticulata had significant antimicrobial activity, and is a promising candidate for further purification and identification of antibacterial compounds.