Anotace:
For many decades, members in the genus Streptomyces have been considered the principal microbial producers of secondary metabolites with antibiotic activity. In this study, we evaluated the inhibitory activity of a cell-free supernatant produced by Streptomyces sp. CACIS-1.16CA against human and plant bacterial pathogens. We also assessed the thermal stability of the compounds. An initial screening to evaluate the antibacterial activity of compounds diffused from a CACIS-1.16CA culture into agar discs found inhibitory effects against Escherichia coli, Staphylococcus aureus, Enterococcus faecalis, Bacillus pumilus, and Pectobacterium carotovorum. A cell-free supernatant from cultured CACIS-1.16CA confirmed the inhibition effects on the susceptible pathogens. Thermally treating the supernatant did not significantly affect the inhibitory activity, indicating Streptomyces sp. CACIS-1.16CA produces some thermally stable antibacterial metabolites. This antibacterial activity is consistent with the detection of biosynthetic gene clusters for polyketide synthase Types I and II and non-ribosomal peptide synthase.