[Evaluation of marine sponge extracts as new sources of antimicrobial substances]

As part of the search for new natural sources of antibiotic compounds, in this study, carried out in the northeastern coast of Colombia, 15 sponge species were collected. A crude organic extract was obtained from each one and evaluated regarding their antimicrobial properties in vitro against microorganisms with clinical importance for humans (one strain for each specie of Streptococcus faecalis, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and Candida albicans). Sponge extracts from Halichondria spp., Petromica ciocalyptoides and Xestospongia proxima exhibited antibacterial activity against gram-positive bacteria and antifungal activity against the fungi, while the sponge Dragmacidon reticulata showed activity only for the same yeast specie. Bioactivity of the extracts was compared with that of both a antibiotic (cefoperazone) and an antimicotic (nistatine). It was found that inhibition values of X. proxima extracts in vitro are, in some cases, higher than those observed for cefoperazone and nistatine. Crude extracts from the sponges Myrmekioderma gyroderma, Myrmekioderma rea, Biemna cribaria, Cinachyrella kuekenthali, Iotrochota imminuta, Oceanapia peltata, Polymastia tenax, Desmapsamma anchorata, Spirastrella coccinea, Cribrochalina infundibulum and Oceanapia bartschi did not show any antimicrobial activity whatsoever.