Identification of Antibiotic-Producing Streptomyces Species in Iran’s soil by Phenotypic and Genotypic Methods
Biotechnology and Health Sciences: February 28, 2018,
5 (1); e59854
February 01, 2018
Article Type: Research Article
April 13, 2017
August 22, 2017
M. Identification of Antibiotic-Producing Streptomyces Species in Iran’s soil by Phenotypic and Genotypic Methods,
Biotech Health Sci.
Introduction: Actinomycetes are gram-positive and filamentous bacteria which include most microorganisms in the soil. According to the researches, three-quarters of all known antibiotics are produced by Actinomycetes. In this regard, screening for antibacterial activities as well as identifying them, 16S rRNA gene and phenotyping methods were used.
The aim of this study was to evaluate actinomycetes in soils of different parts of Iran for their antimicrobial properties and also characterization of active strain using 16S rRNA gene and phenotypic methods.
Methods: Actinomycetes isolates were separated from the gathered soil samples; initial screening have done using cross streak method in agar culture and second screening have done using disk diffusion method against the studied microorganisms: S. aureus, ATCC 25923 and E.coli ATCC 25922. Final confirmation of the produced antibiotic has been conducted by HPLC and identification of strains was done by PCR and DNA sequencing.
Results: From 100 gathered soil samples, 52 actinomycete isolates were separated; 30 isolates of primary screening and 3 isolates of secondary screening were selected. Strain 28 had a peak (RF) similar to gentamicin and isolates 34 and 4 strains had similar peak (RF) to streptomycin in HPLC. 16S rRNA genes of isolates were sequenced, in which isolate 28 had 99.93 percent similarity to Streptomyces youssoufiensis and isolate 4 had 99.93 percent similarity to Streptomyces cyaneofuscatus.
Conclusion: The results showed that there are new isolates in the soil samples of Iran that have the ability to produce antibacterial substances.
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