Characterization of extensively drug-resistant Mycobacterium tuberculosis clinical isolates in China.

Thirteen extensively drug-resistant tuberculosis isolates which were highly resistant to a broad spectrum of antituberculosis drugs were identified from 1,926 clinical isolates in China. They had highly diverse mycobacterial interspersed repetitive-unit-variable-number tandem-repeat patterns. Most, but not all, of the drug target genes had mutations contributing to resistance to the corresponding drug.