Antagonism and Resistance to Antibiotics of Actinomycetes from Soils of Three Specially Protected Natural Territories

Abstract

The relevance of the study of antibiotic resistance of microorganisms in specially protected natural areas is due to the need to control the spread of resistance among human, animal, and plant pathogens. According to the concept of resistome, microorganisms of natural microbial communities, including soil microbial cenoses, contain many antibiotic-resistant genes and actively exchange them. Information on the spread of antibiotic resistance among microorganisms in the habitats undisturbed by economic activity is currently insufficient. Forty-eight strains of streptomycetes were isolated from soils of different geneses: soddy alluvial soil (Fluvisol) in the Nurgush State Nature Reserve (Kirov oblast), mountainous cinnamonic soil (Cambisol) in the Novyi Svet Nature Reserve (Crimea), and brown forest soils (Cambisols) in the Belovezhskaya Pushcha National Park (Belarus). Their antagonistic activity against micromycetes and bacteria was examined. It was shown that the potential of antagonistic action of the isolates from acid soddy alluvial soil exceeds that of the cultures isolated from other two soils. The assessment of resistance of natural isolates to eight antibiotics of different classes and with different mechanisms of action (the inhibitors of synthesis of cell walls, nucleic acid, protein, and metabolic pathways) has revealed specific features that distinguish the resistance spectra of streptomycetes isolated from undisturbed natural soils of different geneses from one another. The findings expand existing concepts of the spread of antibiotic resistance to undisturbed biotopes and are of great interest for assessing the risk of resistance gene transfer from the environment to pathogens.