Characterization of Mycobacterium tuberculosis in Syrian patients by double-repetitive-element polymerase chain reaction.

The role of previous treatment in the dynamics of tuberculosis transmission has not been adequately investigated. Mycobacterium tuberculosis isolates from previously treated patients (n = 88) from all regions of Syrian Arab Republic were characterized in terms of antibiotic sensitivity and genotyping using double-repetitive-element polymerase chain reaction (DRE-PCR) method for the proximity of the repetitive DNA elements IS6110 (a mobile genetic element) and PGRS. The 88 isolates resulted in 59 different DRE-PCR patterns. Correlations related to age, sex, region, sensitivity and genotype were examined. All regions of the country showed high levels of genotype diversity, suggesting a low level of transmission of M. tuberculosis strains in previously treated patients.