DNA Fingerprinting of Resistant Mycobacterium tuberculosis Isolates in Iran by IS6110-RFLP Method

The objective of the research was to identify resistant Mycobacterium tuberculosis strains and recognize their molecular epidemiology and how they are disseminated in order to determine the cause and the effect of drug resistance and the process of its development.          Materials and methods. Genomic deoxyribonucleic acid obtained from 37 drug-resistant Mycobacterium tuberculosis isolates were examined and fingerprinted by the IS6110- restriction fragment length polymorphism method. The data obtained were then analyzed using SPSS statistics software.          Results. The mean patients’ age was 51 ± 15.5 years. There were 46% of male patients, 67.6% of the patients from urban areas, 86.5% of Iranians, 21.6% of relapsed cases, 8.1% of human immunodeficiency virus-positive patients, and 10.8% of the patients with a history of contact with tuberculosis patient. Based on IS6110 - restriction fragment length polymorphism, 30 different genetic types were observed which indicated a significant variation of this pathogen in Markazi province, Iran. The number of cluster genotypes was determined by 6 clusters; the number of unique types was 24. There were no relationships between age, gender, nationality, residence, close contact with tuberculosis patients, recurrence of tuberculosis, positive human immunodeficiency virus status and clustered or non-clustered strain genotype.          Conclusions. Considering the high genetic diversity in Mycobacterium tuberculosis strains, it can be concluded that, based on IS6110 - restriction fragment length polymorphism, about 65% of cases occurred due to reactivation, and 35% of the cases were due to recent transmission. The information obtained through the molecular typing method can be very effective in future planning for tuberculosis control in Iran.