Isolation and Identification Rare Actinobacteria from Persian Gulf and Oman Sea

The widespread use of antibiotics has been led to increased emergence of antibiotic resistant bacteria and high mortality and morbidity rates due to infectious diseases. Pseudomonas aeruginosa is one of the most important causes of nosocomial infections, which shows high resistance to a wide range of antibiotics. So, finding new and effective antimicrobial compounds in order to overcome antibiotic resistant infectious diseases is so critical. Screening of native actinobacteria can be an effective strategy to find novel antimicrobial compounds. The aim of current study was isolation, screening and identification of rare actinobacteria to find the strains which produce antimicrobial compounds against P. aeruginosa. Thirty samples of water and sediments were collected from Persian Gulf and Oman Sea and used for isolation of actinobacterial strains. After isolation of actinobacteria, their metabolites were extracted and their anti-P. aeruginosa activities were investigated. Minimum inhibitory concentration (MIC) of the most efficient extract was determined using broth microdilution method. Finally, the most efficient strain was identified. In this study, all principles of biosafety and bioethics have been considered. Fifty actinobacteria were isolated from water and sediments. Five isolates had considerable antimicrobial activity. MIC value of the most efficient extract against P. aeruginosa was 100 µg/ml. Molecular analysis of 16SrRNA showed that the most effective fermentation broth extract belongs to Micromonospora and has 99.8% similarity to M. chalcea. The current study revealed that the water of southern Iran and their sediments are promising sources of potent rare Actinobacteria in the production of antimicrobial compounds against P. aeruginosa.