Journal of Advanced Biomedical Sciences

en Antimicrobial Activities of the Secondary Metabolite Extracted from a Nocardia Strain ميكروبیولوژی Microbiology پژوهشي Research <div style="text-align: justify;">Background & Objective: The emergence of antibiotic-resistant bacteria and limited treatment options for these infections is a challenging problem in the world. There is increasing interest in isolating bioactive molecules from actinobacteria and elucidating their antimicrobial mechanisms at the moment. The current study aimed to investigate the antimicrobial activities of a Nocardia strain (N4) that was previously isolated from the soil samples in Tehran, Iran.  Materials & Methods: The cultural, morphological, and physiological characteristics of the strain were determined and the identity of the strain was confirmed using 16SrRNA gene sequencing. The strain was screened for antimicrobial metabolite production. The in vitro anti-microbial activity of the extracted metabolite was assessed by agar well diffusion and minimum inhibitory concentrations methods. Finally, the structure of the extracted metabolite was confirmed by HPLC and mass spectrometry methods. Results: The isolate shared 99% sequence similarity with Nocardia soli. The strain showed broad-spectrum antimicrobial activities against some pathogenic bacteria (Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853, Klebsiella pneumoniae ATCC 700603, Salmonella Typhimurium ATCC 14028 and Shigella sonnei RI366) and fungi (Aspergillus niger ATCC 1015 and Aspergillus fumigatus ATCC 1022) in the agar well diffusion method. The ethyl acetate extract of the strain exhibited the highest antimicrobial activity against E. coli (MIC= 4.67±3.055 μg/mL) and K. pneumoniae (MIC=3.33±1.155 μg/mL). The metabolite showed high similarity with C21H28N7O14. Conclusions: The current study confirmed the presence of a bioactive metabolite in strain N4, suggesting that this may be a promising candidate for discovering bioactive components with broad antibacterial activities against a variety of pathogens Keywords: </div> Nocardia soli, antimicrobial activity, HPLC, Bioactive Metabolite 203 214 http://jabs.fums.ac.ir/browse.php?a_code=A-10-2988-1&slc_lang=en&sid=1 Marjan Seratnahaei مرجان صراط نهائی Marjan.nahaee@gmail.com 100319475328460026112 100319475328460026112 Yes Department of Microbiology, Faculty of Basic Sciences, North Tehran Branch, Islamic Azad University, Tehran, Iran گروه میکروبیولوژی، دانشکده علوم پایه، واحد تهران شمال، دانشگاه آزاد اسلامی، تهران، ایران Seyyed Saeed Eshraghi سید سعید اشراقی saeedeshraghi4@gmail.com 100319475328460026113 100319475328460026113 No Department of Pathobiology, Faculty of Public Health, Tehran University of Medical Science, Tehran, Iran گروه پاتوبیولوژی، دانشکده بهداشت، دانشگاه علوم پزشکی تهران، تهران، ایران Parviz Pakzad پرویز پاکزاد Parviz_pakzad@yahoo.com 100319475328460026114 100319475328460026114 No Department of Microbiology, Faculty of Basic Sciences, North Tehran Branch, Islamic Azad University, Tehran, Iran گروه میکروبیولوژی، دانشکده علوم پایه، واحد تهران شمال، دانشگاه آزاد اسلامی، تهران، ایران Alireza Zahraei Ramazani علیرضا زهرائی رمضانی alirezazahraei@yahoo.com 100319475328460026115 100319475328460026115 No Department of Medical Entomology and Vector Control, Faculty of Public Health, Tehran University of Medical Sciences, Tehran, Iran گروه حشره شناسی پزشکی و کنترل ناقل، دانشکده بهداشت، دانشگاه علوم پزشکی تهران، تهران، ایران Mehdi Yaseri مهدی یاسری myaseri@tums.ac.ir 100319475328460026116 100319475328460026116 No Department of Epidemiology and Biostatistics, Tehran University of Medical Sciences, Tehran, Iran گروه اپیدمیولوژی و آمار زیستی، دانشگاه علوم پزشکی تهران، تهران، ایران