Abstract

Introduction. The rapid transference and dissemination of resistance genes among different microbial populations and the spread of multidrug-resistant bacterial pathogens necessitates the search for novel or alternative antibacterial agents. Therefore, research of microorganisms in poorly explored areas with unusual environments to avoid redundancy in isolation of compounds and actinomycetes has become important. The antarctic continent is one of the most extreme and pristine places on earth. Consequently, as abiotic factors become more intense with the increase in latitude, the selection pressures in antarctic represent a unique opportunity to investigate and exploit the biodiversity of unexplored microbial communities goal: the aim is characterize the production of antibacterial compounds and their effects against multiresistant bacterias, minimum inhibitory concentration (MIC) against susceptible bacterias and the toxicity of crude extract. Materials and methods. The culture was incubated at 3 different temperature for 7 days. Extraction of compounds was made from the cellfree culture supernatant using ethyl acetate. Bacterial inhibitory assay was carried out against 7 multi-resistant bacteria, Staphylococcus aureus (ATCC6538p) and L. monocytogenes. LB agar seeded with target strain was poured over the spots of TLC chromatograpHy. Toxicity was evaluated by brine shrimp lethality test. Results. The strain produce in oatmeal medium at least eleven antimicrobial substances active. The compound production is higher at 12°C than at 28°C. Significant antibacterial activity was showed only against Staphylococcus aureus and Listeria monocytogenes. The MIC were 1 and 10 μg/mL, respectively. The LC50 for Artemia sallina was 24,6 ug/mL.Conclusions. The extract showed compounds with interesting activity against Listeria monocytogenes (ISP) that deserve to be purified and tested to further use.