Antimicrobial Activity of Antibiotic Producing Streptomyces macrosporus

Abstract

The aim of the present study was to isolate and to identify the actinomycetes having antimicrobial activity. Actinomycetes strain isolated from soil samples collected at the Coimbatore region, Tamilnadu, India. Actinomycetes were isolated by spread plate technique and screening was done by parallel streak & agar well diffusion method. Upon primary screening by parallel streak method out of 180 actinomycetes isolates around 25 isolates showed antimicrobial activity against test organisms. On secondary screening out of 25 isolates, 9 isolates showed activity. According to antimicrobial activity and spectrum broadness strain 7 was selected for further study. Based on the morphological, physiological, biochemical and phylogenetic characterization the strain 7 was identified as Streptomyces macrosporus. In conclusion the isolated strain has broad spectrum of antimicrobial activity against the test organisms. I. Introduction Search for new antibiotics effective against multidrug resistant pathogenic bacteria is presently an important area of antibiotic research. Natural products having novel structures have been observed to possess useful biological activities, soil is a natural reservoir for microorganisms and their antimicrobial products (1). Of all known drugs 70% have been isolated from actinomycetes of which 60% are used in medicine & agriculture respectively. Streptomyces spp produce about 75% of commercially and medically useful antibiotics that are natural in origin such as erythromycin, Neomycin, tetracycline and Cefoxitin. Microorganisms constitute an in exhaustible reservoir of compounds with pharmacological, physiological, medical (or) agricultural applications.