Identification of Mycobacterium spp. isolates from suspected tuberculosis patients using molecular method in Zahedan, IRAN

Document Type : Original Articles

Authors

1 Department of Microbiology, Razi Vaccine and Serum Research Institute, Agricultural Research, Education and Extension Organization (AREEO), Karaj, Iran

2 Department of Microbiology, Razi Vaccine and Serum Research Institute, Agricultural Research, Education and Extension Organization (AREEO), Karaj, Iran.

3 Department of Parasitology and Mycology, School of Medicine Infectious Diseases and Tropical Medicine Research Center, Research Institute of Cellular and Molecular Sciences in Infectious Diseases Zahedan University of Medical Sciences.

4 Department of Anaerobic Bacterial Vaccine Production and Research, Razi Vaccine and Serum Research Institute, Agricultural Research, Education and Extension Organization (AREEO), Karaj, Iran.

10.22092/ari.2025.369896.3715

Abstract

Tuberculosis is one of the oldest zoonotic diseases, with a high prevalence in many low-income countries. Specific and sensitive tuberculosis diagnostic methods in the early stages play a significant role in the life-saving of patients. There is little data available in Zahedan on the prevalence of the Mycobacterium species, so this study aimed to identify the Mycobacterium species in patients with pulmonary tuberculosis in Zahedan. This study included 500 samples collected from sputum from Zahedan. The samples were cultured on LJ, and simultaneously stained with cold ZN. After growth, DNA was extracted and used for molecular identification of the Mycobacterium species from samples. RD typing was used to differentiate members of the Mycobacterium tuberculosis complex. Finally, the PCR-RFLP method was used as a comparison method. The typical 543 bp band was observed in all isolates via amplicon PCR-16S rRNA, emphasizing that all isolates belong to the genus Mycobacterium. Sixty isolates were identified as belonging to the MTBC and were classified as M. tuberculosis species. The PCR-RFLP analysis using Alu I on the oxyR gene confirmed that all 60 isolates were M. tuberculosis. Three samples (4.7%) were also positive for NTM. One isolate was categorized in the M. terrae complex group (MTC), and two isolates belonged to M. simiae group. Our results indicated that M. tuberculosis has a high prevalence in the human population of this city. Therefore, screening these individuals plays a significant role in reducing the disease prevalence in Zahedan. It is suggested further studies on the human population to find Mycobacterium strains in the future.

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