Molecular Epidemiological Interpretation of the Epidemic of Extensively Drug-Resistant Tuberculosis in South Africa

We show that the interpretation of molecular epidemiological data for extensively drug-resistant tuberculosis (XDR-TB) is dependent on the number of different markers used to define transmission. Using spoligotyping, IS6 110 DNA fingerprinting, and DNA sequence data, we show that XDR-TB in South Africa (2006 to 2008) was predominantly driven by the acquisition of second-line drug resistance.