Genotyping of rifampin-resistant Mycobacterium tuberculosis isolates from western Turkey

Although the rate of multiple drug resistance is high, there is no published data on the transmission rate of drug-resistant strains of Mycobacterium tuberculosis in the Aegean region of western Turkey that are based on molecular methods.

IS6110 and pTBN12 restriction fragment length polymorphism (RFLP) methods were used for typing M. tuberculosis strains isolated from 26 sputum samples from 26 patients.

Nineteen of the rifampin-resistant isolates (73.1%) contained 6 to 11 copies of IS6110. Eighteen different IS6110 DNA fingerprint patterns were observed in the 26 rifampin-resistant isolates. Twenty-three of the 26 rifampin-resistant isolates were also resistant to isoniazid. When evaluated together, both methods yielded 21 (80.9%) different banding patterns and the level of clustering was 34.6%. The average number per pattern was 1.23 (26/21).

IS6110 fingerprinting suggests that the rifampin-resistant isolates obtained from the Aegean region had a relatively high clustering rate and were clonally related. These findings showed that the rifampin-resistant isolates are actively transmitted between patients. Urgent measures should be taken to prevent the spread of these resistant strains.