Background and Aim: Due to the emergence of bacterial resistance to antibiotics used, searching for new sources in order to make an important discovery of effective drugs is of great impportance. According to numerous studies, Actinobacterials are one of the largest groups of bacteria to produce the antimicrobial compounds. Actinomycetes are a unique group of bacteria that are widely distributed in natural ecosystems, particularly soil and have a special role in the production of secondary metabolites. Methods:Sampling was performed from Telar forests of northern Iran. Isolation of Actinobacteria on caseinstarch agar and glycerol-casein agar medium at 25 °C was performed. A total of 172 isolates were obtained, based on morphological characteristics the 55 isolates are belonging to Actinobacteria. To examine the ability to produce antimicrobial compounds, cross-culture method was used against reference and pathogen strains of Gram-positive bacteria such as Staphylococcus epidermidis, S.intermedius and methicillin-resistant S.aureus and gram-negative bacteria such as Pseudomonas, Listeria, Klebsiella, Salmonella, Acinetobacter, and E.coli O157 on Mueller Hinton agar. Antimicrobial effectiveness was evaluated by inhibition zone. Results:Results of the research are shown that 32 isolates of Actinobacteria have antimicrobial compounds. The predominant isolates have antimicrobial compounds against S.saprophyticus among Gram-positive bacteria and Listeria amonog reference gram-negative bacteria. According to the inhibition zone, 11 isolates produced the most antimicrobial compounds. 3 of them had activity against both positive and negative reference bacteria. Conclusion:Primary results show the existence of Actinobacteria producing antimicrobial compounds in natural ecosystems. Evaluation of molecular characteristics of the isolates and extraction of antimicrobial compounds against the mentioned pathogenic bacteria are in progress.

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