Antimicrobial and Cytotoxic Characteristics of Antibiotic Streptofungin

Abstract

Background. Streptomycetes were and remain a source of new antimicrobial compounds of various nature. A new wave of interest in such research is associated with the possibilities of applied genomics to reveal the hidden biosynthetic potential of streptomycetes, and therefore the discovery of new practically valuable antimicrobial products. The problem of antibiotic resistance of pathogens can be solved by creating compositions of active substances of different nature to overcome the protective mechanisms of pathogens.
 Objective. The purpose of the work was to establish and evaluate the antimicrobial and cytotoxic characteristics of the new antibiotic streptofungin, synthesized by Streptomyces albus 2435 (CMIM-S-668) and its mutant strains 2435/М, UN44, 4S, US101, AE6, 105, 80/5.
 Methods. To establish the characteristics of streptofungin, the antagonistic activity of selected S. albus producer strains was determined (by the radial streak method), the minimum inhibitory concentration of the antibiotic (by the serial dilution method), and cytotoxicity was determined by the MTT test with resazurin.
 Results. The activity of the antibiotic streptofungin against Candida fungi (C. albicans, C. utilis) is shown. Minimum inhibitory concentrations of streptofungin were determined for C. albicans ATCC 10231 (10 μg/ml), B. subtilis ATCC 6633 (200 μg/ml) and P. aeruginosa ATCC 9027 (500 μg/ml). According to the resazurin test, streptofungin does not show a cytotoxic effect in a wide range of concentrations from 2.5 to 500 μg/ml, and therefore can be considered potentially permissible for humans and animals in the studied concentrations.
 Conclusions. The antagonistic activity of mutant strains of S. albus culture is due to the action of a complex of antimicrobial products that have a different antimicrobial spectrum and mechanism of action. The obtained results give reasons to consider streptofungin as a promising pharmaceutical substance with antifungal action, as well as to consider the possibility of its combination with the bacteriolytic enzyme complex of the same culture for the development of an antimicrobial agent with a wide spectrum of action.