Molecular and Phenotypic Characterization of Novel Streptomyces Species Isolated from Kurdistan Soil and its Antibacterial Activity Against Human Pathogens

Abstract

of more than 70% of clinical antibiotics; researchers have been shedding light on the genus Streptomyces in hope of discovering novel species with the ability to produce effective and efficient molecules against superbugs. This study aims to investigate different sources of Kurdistan soil for the existence of novel Streptomyces species that possess bioactive compounds. So, twenty soil samples were obtained from agricultural soil, house garden soil, cave soil, and soil contaminated with petroleum. Selective media combined with morphological characterisation, biochemical tests and molecular techniques were used for species identification. Only fifty-eight bacterial samples were given a positive PCR product in which thirtyone 16S rDNA sequences were compared with previously existed prokaryotic DNA sequences using the EzTaxon database. Twenty-nine out of thirty-one samples showed >99% similarity to previously cultured Streptomyces spp. and two isolates from house garden soil samples were candidates to be novel species, and they have shown antibacterial activity against E. coli (ATCC 25218) and Staphylococcus aureus (ATCC 25923) by inhibiting their growth on Mueller-Hinton agar plate using cross streak method.