مولكولار تايپينگ ايزوله هاي مايكوباكتريوم توبركلوزيس به روش IS6110-RFLP

Molecular Typing of Mycobacterium tuberculosis by IS6110-RFLP Method

Abstract Background and objective: Molecular genotyping methods are important in detecting the dominance of transmission or reinfection in a population.IS6110 – RFLP typing remains the international accepted standard and continues to provide new insights in the epidemiology of mycobacterium tuberculosis infections. Genetic basement of IS6110 is because of different copies and places in different mycobacterium species genomes. Materials and methods: During one year study genotyping of 100 of M. tuberculosis (M.t.) isolates from patients referred to Pasteur Institute of Iran were accomplished with IS6110-RFLP typing method. The IS6110 DNA probe was prepared with amplification of 245 bp-fragment using PCR method. This fragment was purified and labeled by digoxigenin. Enzymatic digestions were accomplished on extracted DNA of all Mycobacterium tuberculosis isolates using PvuII enzyme. After hybridization and detecting procedures the RFLP patterns were analyzed with GelcomparII software. Result: According to the obtained dendrogram 35 common types (CT) and 17 single types (ST) and 3 predominant CTs were detected. We could not find any meaningful relation between antibiotypes and genotypes. Four MDR TB strains isolated among studied population. Conclusion: According to our study the finding that 3 prevalent genotypes constituted 21% of the isolates show limited transmission rate among studied population. On the other hand high diversity among the rest of genotypes maybe due to newly acquired TB which is urgent need for TB control program. This will be value when compared with other characteristics such as level of virulence or antibiotic resistant pattern of isolates. Because of the different antibiotic resistant patterns in predominant common type isolates and the presence of MDR isolates among these types the monitoring of TB patients during antibiotic therapy is essential for prevention of spreading MDR-TB isolates in population.