ANTAGONISTIC PROPERTIES OF THE BLACK SEA STREPTOMYCETES ISOLATED FROM THE FOULING OF SHELL ROCK AND MUSSELS

Abstract

SummaryThe rapid emergence of resistance by bacterial and fungal pathogens is a serious problem in the health care system, which causes the search for new promising producers of antimicrobial natural products in various ecological niches. Aim. To determine the antagonistic activity of streptomycetes isolated from the biological fouling of natural shell rock and mussels of the Odesa gulf of the Black Sea. Methods. The antagonistic activity of 19 and 14 strains of streptomycetes isolated from the fouling of shell rock and mussels of the Odesa gulf, respectively, were investigated. Streptomycetes were pre-cultivated on agar media Gause 1, Gause 2 and oat agar with sea salt (2%) at a temperature of 30 °C for 10 days. Antagonistic activity against 12 test cultures was determined by the block method. Results. All isolated marine streptomycetes are antagonists of at least one strain of the indicator microorganism. Antibiotic activity depended on the source of the streptomycetes isolation, culture medium and properties of specific strains of both producers and test cultures. The best activity of streptomycetes strains from shell rock was shown after cultivation on Gause 1 medium, and streptomycetes from mussels – after cultivation on Gause 2 medium. The zones of no growth of sensitive indicators ranged from 12,4±0,3 mm to 20,6±0,2 mm (under the influence of streptomycetes from shell rock) and from 12,4±0,2 mm to 39,7±0,2 mm (under the influence of streptomycetes from mussels). Streptomyces sp. Lim 2.2 (strain from a shell rock) inhibited the growth of 8 test cultures, and strains from mussels Streptomyces sp. Myt 4b and Myt 7ch – 10 test cultures. Indicator strains of gram-positive bacteria were the most sensitive to all streptomycetes, in particular, strain Staphylococcus aureus ATCC 25923 was most inhibited by metabolites of Streptomyces spp. Myt 12a and Myt 12b. Conclusions. Antagonistic activity of streptomycetes isolated from the Black Sea depended on the source of isolation, pre-cultivation medium and properties of both producer strains and indicator microorganisms. The greatest activity of streptomycete strains from shell rock and mussels was shown after preliminary cultivation, respectively, on Gause 1 and Gause 2 media against gram-positive bacteria. The best antibiotic potential was found in strains of Streptomyces sp. Lim 2.2, Lim 4, Lim 5.1 and Lim 7.2, isolated from the fouling of shell rock, and strains of Streptomyces sp. Myt 7b, Myt 7ch, Myt 12a and Myt 12b isolated from mussels.