Isolation and Characterization of Streptomyces diastaticus from Soil and Evaluation of Its Activity Against some Human Pathogenic Microorganisms

Abstract

The dominance of multidrug-resistant pathogenic microorganisms, which are difficult to control, has necessitated the search for new therapeutic agents. Streptomyces bacteria are among the most prolific producers of secondary metabolites, including antibiotics. Strains of Streptomyces were isolated from soil collected in the garden of the Faculty of Science. The soil samples were cultured on three types of growth media. The colonies were characterized by the formation of a white aerial mycelium and a substrate mycelium embedded in the medium with a light brown to dark brown color, along with multiple hooked spore chains. with diffusible pigments were observed in the medium. Based on Bergey’s Manual of Systematic Bacteriology and genetic analysis at the Aotomic Energy Comission, the bacterial isolate was identified as Streptomyces diastaticus. This isolate exhibited antibacterial activity against human pathogenic bacteria, including
 Gram-negative (Escherichia coli,) and Gram-positive (Staphylococcus aureus, Entrococcus faecalis) strains. The inhibition zone diameters of the ethyl acetate extract of S. diastaticus ranged from 6 to 11 mm against P. aeruginosa, and from 11 to 17 mm against S. aureus