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

Abstract

Screening of microorganisms for the production of novel antibiotics has been intensively<br />pursued for many years by scientists. Actinomycetes have the capability to synthesize many<br />different antibiotics. A total of 69 actinomycete isolates were recovered from soil samples<br />collected from Alborz Province. Selected colonies (rough, chalky) of actinomycetes were<br />purified. All screened isolates were identified morphologically and physiologically. And all of<br />them belong to the Streptomyces genus. These were then assessed for their antibacterial activity<br />against pathogenic bacteria. Four pathogenic test strains were used in this study including<br />Staphylococcus aureus ATCC 6538, Bacillus subtilis ATTC 6633, Klebsiella pneumoniae<br />ATTC 10031, and Escherichia coli ATCC 29998. Determination of antibacterial activities of<br />isolated actinomycetes performed by using modified spektra-plak method and Mueller Hinton<br />agar (Oxoid) plates. Antagonism was detected by formation of inhibition zone. Results of the<br />study indicated that 12 isolates were active against S. aureus, 15 isolates against B. subtilis, six<br />isolate against K. pneumonia, and four isolate were active against E. coli.