Antibacterial activity of some actinomycetes isolated from soils of Alborz province, Iran

Screening of microorganisms for the production of novel antibiotics has been intensivelypursued for many years by scientists. Actinomycetes have the capability to synthesize manydifferent antibiotics. A total of 69 actinomycete isolates were recovered from soil samplescollected from Alborz Province. Selected colonies (rough, chalky) of actinomycetes werepurified. All screened isolates were identified morphologically and physiologically. And all ofthem belong to the Streptomyces genus. These were then assessed for their antibacterial activityagainst pathogenic bacteria. Four pathogenic test strains were used in this study includingStaphylococcus aureus ATCC 6538, Bacillus subtilis ATTC 6633, Klebsiella pneumoniaeATTC 10031, and Escherichia coli ATCC 29998. Determination of antibacterial activities ofisolated actinomycetes performed by using modified spektra-plak method and Mueller Hintonagar (Oxoid) plates. Antagonism was detected by formation of inhibition zone. Results of thestudy indicated that 12 isolates were active against S. aureus, 15 isolates against B. subtilis, sixisolate against K. pneumonia, and four isolate were active against E. coli.