Antibiotic Potential of Marine Actinomycetes of the Genera Streptomyces and Nocardiopsis

Due to the emergence of antibiotic resistance in pathogenic microorganisms, it is urgent to search for producers of new antimicrobial metabolites. Actinomycetes are gram-positive mycelial bacteria that produce a large number of antibiotics used in medicine and the agro-industrial complex. Currently, researchers are focused on the search for actinomycetes in ecological niches such as freshwater and marine reservoirs, zones with extreme natural conditions (permafrost soils, glaciers, desert, saline soils, etc.). In this study, cultures of marine actinomycetes were restored after 15 years of storage under vaseline oil. It was shown that all strains retained viability and antibiotic activity at a high level. Based on the results of 16S rRNA gene sequence analysis, the species were identified as: Streptomyces sampsonii 6N, Streptomyces sampsonii 8N, Streptomyces sampsonii 521N, Streptomyces halstedii 22N, Streptomyces brevispora 12N, Streptomyces hirsutus 23N, Streptomyces niveus 14N, Nocardiopsis alba 24N, Nocardiopsis alba 73N, Nocardiopsis alba 85N, Nocardiopsis alba 106N, Nocardiopsis alborubida 722N, Nocardiopsis umidischolae 755N, Nocardiopsis umidischolae 763N. These strains of actinobacteria possessed significant antibiotic activity against the following pathogens: Micrococcus luteus ATCC 9341, Staphylococcus aureus INA 00985, Bacillus subtilis ATCC 6633, Staphylococcus aureus INA 00761 (MRSA — Staphylococcus aureus), Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853, Pectobacterium carotovorum VKM-B1247, Saccharomyces cerevisiae INA 01042, Candida albicans ATCC 14053, Aspergillus niger ATCC 16404, Aspergillus fumigatus CPB F -37, Fusarium solani VKPM F-890, Fusarium oxysporum VKPM F-148. Therefore, this study evaluated the marine actinomycetes can be potential producers of the novel antibiotics.