Defined as M tuberculosis infection that is resistant to isoniazid and rifampin.
XDR-TB refers to extensively drug resistant TB to isoniazid, rifampin, fluoroquinolones, and second line drugs such as kanamycin, alizarin or capreomycin.
It affects almost 500,000 new individuals worldwide each year.
It is considerably more difficult to treat than drug-susceptible TB.
India and China have the greatest burden of disease, accounting for almost 50% of the world’s cases.
WHO estimated multi drug resistant pulmonary tuberculosis cases at nearly 450,000 worldwide in 2012.
In 2013, 480,000 new cases were estimated to have occurred worldwide resulting in about 210,000 deaths.
Global prevalence of multi drug-resistant tuberculosis estimated at 3.6% of the newly diagnosed cases and 20.2% of previously treated patients.
In 2017 it was an estimate 558,000 cases and 230,000 deaths worldwide.
The prevalence of multi drug resistant tuberculosis is much higher in some areas of the Russian Federation.
More than three fourths of estimated cases occur in previously untreated patients.
The highest proportion of MDR tuberculosis, and the most severe drug resistant cases appear in the countries of the former Soviet Union.
XDR-tuberculosis accounts for 10% of all cases of MDR tuberculosis.
Vast majority of cases are not diagnosed, or if diagnosed, or mismanaged.
Transmission occurs in the community.
Rapid molecular tests for MDR a tuberculosis are available.
The combination of bedaquiline, pretomanid, and linezolid led to a favorable outcome at six months after the end of therapy in a high percentage of patients with highly drug resistant forms of tuberculosis.
Bedaquiline-pretomanid-linezolid regimen has a 90% efficacy against highly drug-resistant tuberculosis.