Genetic diversity of Mycobacterium tuberculosis isolates at the Military Medical Academy in Ankara, Turkey

Genotyping of Mycobacterium tuberculosis isolates from infected individuals can play an important role in tracking the source of infection and unraveling the epidemiology of a tuberculosis pandemic. A total of 114 M. tuberculosis isolates were genotyped by spoligotyping and results were compared with an international spoligotype database (SpoIDB4). Twenty-one spoligotyping-defined clusters including 97 patients were established, and an additional 17 unique patterns were found. Ninety-eight (85.9%) isolates belonged to previously defined shared types (STs). The ST53 (ill-defined T1 superfamily, n = 31), ST41 (LAM7-TUR family, n = 9), ST118 (T undefined, n = 8) and ST50 (Haarlem 3, n = 6) were four major clusters of our isolates. After comparison with the international SpoIDB4 database, two new intrafile clusters, ST2136 and ST2139, were created and two new interfile clusters, ST2135 and ST2140, were defined. Eight (7%) of the 17 isolates with unique patterns were found to be orphans, whereas the STs of 9 isolates had previously been deposited in the international SpoIDB4 database. In addition, two isolates with an ST pattern characteristic of the Beijing family of M. tuberculosis were found. This study shows that, although ubiquitous spoligotypes are common, several spoligotypes specific to Turkey also exist. Thus, our study may help us to better understand the spread of M. tuberculosis genotypes to Turkey.