Broad-spectrum antimicrobial activity of wetland-derived Streptomyces sp. ActiF450

The increased incidence of invasive infections and the emerging problem of drug resistance particularly for commonly used molecules have prompted investigations for new, safe and more effective microbial agents. Actinomycetes from unexplored habitats appear as a promising source for novel bioactive compounds with a broad range of biological activities. Thus, the present study aimed to isolate effective wetland-derived actinomycetes against major pathogenic fungi and bacteria. Water samples were collected from various locations of Fetzara Lake, Algeria. Thereafter, an actinomycete designated ActiF450 was isolated using starch-casein-agar medium. The antimicrobial potential of the newly isolated actinomycete was screened using the conventional agar cylinders method on Potato Dextrose Agar (PDA) against various fungal and bacterial pathogens. A wetland-derived Streptomyces sp. Actif450 was identified as Streptomyces malaysiensis based on its physiological properties, morphological characteristics, and 16S rDNA gene sequence analysis. The antimicrobial activity of Streptomyces sp. ActiF450 showed a potent and broad spectrum activity against a range of human fungal pathogens including moulds and yeasts, such as Arthroderma vanbreuseghemii, Aspergillus fumigatus, A. niger, Candida albicans, C. glabarta, C. krusei, C. parapsilosis, Fusarium oxysporum, F. solani, Microsporum canis, Rhodotorula mucilaginous and Scodapulariopsis candida. In addition, high antibacterial activity was recorded against pathogenic staphylococci. The novel Streptomyces sp. ActiF450 may present a promising candidate for the production of new bioactive compounds with broad-spectrum antimicrobial activity.