The rapid increase of antibiotic resistance has become a global health concern, highlighting the urgent need for new antimicrobial agents. Streptomyces species are well known for their ability to make up a wide range of antibiotics and remain an important source in search for novel bioactive compounds. In this study, streptomyces strains were isolated from soil samples of Erbil governorate to evaluate its antimicrobial activity. Twenty five colonies of Streptomyces have been isolated from soils samples collected from (Sherwan Mazn, Bedial, Barbzin, Kelashin, Grk, Kani Piran, Roste, Goshin, Lerabir, Maran, Garwazin, Smilan, Sharbazher, Dezo, Haspaw, Hawler, Prushkin, and Hulgurd). These colonies were further evaluated for their antimicrobial potential using the streak method and well diffusion method against selected microorganisms. In addition, gas chromatography-mass spectrometry (GC-MS) analysis will be conducted to examine secondary metabolite profiles. The results will be added to the report after few days. In addition, the performance of different culture media, i.e. starch casein agar (SCA), oatmeal agar, and L-asparagine glycerol agar- was assessed for the isolation of streptomyces from soil samples. Following incubation, SCA supported more consistent and abundant growth of streptomyces compared to L-asparagine glycerol agar, where growth was poor. Antibiotics like gentamycin and streptomycin inhibited the growth of Streptomyces. Shifting of SCA by replacing gentamicin and streptomycin with rifampicin maintained its effectiveness on well grown streptomyces . Fungal contamination was reduced through the combined use of nystatin and amphotericin B, which was more effective than nystatin being used alone. Additionally, pretreatment of soil for 30 minutes in oven at 60 C° degree reduced the growth of fast-growing bacteria and non-spore forming bacteria, thus supporting the isolation of spore forming actinomycetes more specifically streptomyces . We succeeded to isolate a number of different Streptomyces colonies, which most show antibiotic production due to their ability to inhibit the growth of some other bacteria like Staphylococcus, Klebsiella, and E. coli.
