First insight into the genetic diversity of Mycobacterium tuberculosis strains from patients in Duhok, Iraq

The aim of this study was to evaluate the genotypic diversity of Mycobacterium tuberculosis strains using IS6110 RFLP, spoligotyping and MIRU-VNTR typing. Between June 2008 and June 2009, all smear positive pulmonary specimens were collected prospectively at the national tuberculosis program [NTP] center of Duhok province. The specimens were processed for culture by modified Petroff's method and were inoculated into two tubes of L?wenstein-Jensen [LJ] media. The isolates were identified asM. tuberculosis by using biochemical tests and growth rate. Molecular fingerprinting of all M. tuberculosis strains was performed by IS6110 RFLP, spoligotyping and MIRU-VNTR. M. tuberculosis strains were isolated from 53 Iraqi patients with pulmonary TB. Spoligotyping of M. tuberculosis isolates showed T family [30%] as the predominant genotype. By using the three molecular techniques, there were four spoligotyping clusters of strains ["3540 and 3516", "3565 and 3563", "3605 and 3618" and "865, 877 and 13811"]. Complete concordance with RFLP was observed in one cluster of spoligotyping, but no concordance with MIRU-VNTR profile [234426153433 and 236424183433]. Molecular fingerprinting methods are vital for differentiating a reactivation of latent infection from a recent transmission; however, it should be coupled with clinical epidemiological investigation. The low clustering rate in this study suggests that either reactivation of latent infections may be the main driving force for the endemic situation of the disease in Duhok, or it may indicate that a big circle of TB transmission is missed in the community, which means effective control measures have not been achieved yet in Duhok

First insight into the drug resistance pattern of mycobacterium tuberculosis in Dohuk, Iraq: using spoligotyping and MIRU-VNTR to characterize multidrug resistant strains

The objectives of this study were to determine drug resistance pattern in new and previously treated tuberculosis [TB] patients, to assess function of TB control program, and to characterize multidrug resistant TB [MDR-TB] by molecular fingerprinting methods. Anti-micorbial susceptibility testing [AST] to the first line anti-TB drugs was performed on L?wenstein-Jensen [middlebrook 7H10] medium according to the proportion method. Molecular fingerprinting of all MDR strains was performed by spoligotyping and MIRU-VNTR. Mycobacterium tuberculosis strains were isolated from 53 Iraqi patients with pulmonary TB. Thirty eight patients [71.7%] tested cases, and 15 [28.3%] were previously treated. Four of the 38 new cases [10.5%] had resistant, of which 3 [7.9%] were MDR. Eight [53.3%] of the 15 previously treated patients had resistant strains, of which 7 [46.7%] were MDR. Spoligotyping of MDR strains showed CAS family [40%] as the predominant genotype. Using MIRU-VNTR typing, all isolates had a unique profile. MDR-TB prevalence is higher among previously treated patients than among the new cases. The many drug resistant strains, in absence of evidence of recent transmission and in combination with the many previously treated cases, highlight the need for an improved control program, coupled with a need to improve detection rate and early diagnosis of MDR-TB