ANTIBACTERIAL AND ANTIBIOFILM ACTIVITIES OF BRAZILIAN MARINE-DERIVED FUNGI AGAINST PSEUDOMONAS AERUGINOSA

Marina Scopel (UFRGS); Alexandre José Macedo (UFRGS); Wolf-rainer Abraham (HZI); Amélia Teresinha Henriques (UFRGS)

The increase observed on researches employing marine microorganisms has been evident during the last two decades. The chemical diversity of their secondary metabolites reported to date, has been showing an important potential to the discovery of new molecules with relevant biological activities^1,2. Lately, studies concerning antimicrobial activities have been one of the greater targets for scientists due to the increase on bacteria resistance in hospital environment. Whitin this context, the biofilm formation can be observed through endogenous (f. e. cystic fibrosis³ and osteomyelitis⁴) as well as exogenous (f. e. catheters⁵ and implants⁵) origin, both as an aspect supporting the most important generalized bacterial injuries. Therefore, this study aims at the investigation of the antimicrobial and antibiofilm potentials from fungi associated to marine organisms. Forty-two fungi associated to different marine organisms from South Brazil coast were isolated employing distinct culture media. The initial screening was carried out with microorganisms cultivated during seven, fourteen and twenty one days in Sabouraud broth on static mode. The liquid medium and mycelia were separated by vaccum filtration and kept frozen; the mycelia extracts were then obtained using ethyl acetate as solvent extractor by turbolysis. The antimicrobial activity was evaluated employing liquid medium samples and mycelia extracts against Pseudomonas aeruginosa ATCC 27853. The potential activity towards biofilm formation and degradation of the biofilm previously formed was tested with the liquid medium samples. The agar diffusion test and the cristal violet methods were used for the anti-biofilm screening tests. Results showed antibacterial activity for two liquid medium and for at least twenty mycelia extracts, mainly on seven and twenty one fermentation days. As to the activity on the biofilm formation, four liquid medium presented positive effects, and nine promoted the degradation of the previously formed biofilm, both with less than fifty per cent of inhibition of the formation and degradation. In summary, these results encourage us to perform further research into the chemical composition characterization for these compounds.