Prevalence, associated factors, outcomes and transmission of extensively drug-resistant tuberculosis among multidrug-resistant tuberculosis patients in São Paulo, Brazil: a cross-sectional study

The prevalence of XDR-TB in the state of São Paulo is close to that estimated globally. Most of the XDR-TB patients were treated previously for TB and presented the lowest successful outcome rates. Because transmission of XDR-TB occurred, it is important that timely diagnosis of drug resistance is performed.