IS6110 dot blot hybridization for the identification of Mycobacterium tuberculosis complex

To explore a simple, rapid, and inexpensive way to identify Mycobacterium tuberculosis complex culture, dot blot hybridization using IS6110 as the marker was performed against 2788 known clinical isolates of mycobacteria including M. tuberculosis (n = 721), M. kansasii (177), M. marinum (10), M. avium complex (700), M. terrae complex (203), M. fortuitum (476), M. chelonae (439), and other nonpigmented Runyon's Group IV mycobacteria (62). We found that the sensitivity and specificity of the test were 94.3% and 100%, respectively. When this method was evaluated in a laboratory blind study of 1253 initially unknown clinical isolates, its sensitivity and specificity were 91.2% and 100%, respectively. Because this identification test is technically simple, rapid, and can be done in batches, together with its high sensitivity and specificity, it is a cost-effective method for routine identification of M. tuberculosis complex in laboratories of areas with a high incidence of tuberculosis.