Global distribution of Mycobacterium tuberculosis spoligotypes.

Since the publication of the second version of our spoligotypes database on Mycobacterium tuberculosis (1), the causative agent of tuberculosis (TB), the proportion of clustered isolates (shared types [STs]) increased from 84% (2,779/3,319) to 90% (11,708/13,008). Fifty percent of the clustered isolates were found in only 20 STs. Three of these isolates are M. bovis, including M. bovis BCG (ST 481, 482, and 683). The addition of the next 30 most frequent STs increased the total proportion of clustered isolates (65% instead of 50% initially). A total of 36 potential subfamilies or subclades of M. tuberculosis complex have been tentatively identified, leading to the definition of major and mi…