Additional Drug Resistance in Mycobacterium tuberculosis Isolates From Resected Cavities Among Patients With Multidrug-Resistant or Extensively Drug-Resistant Pulmonary Tuberculosis

The pathogenesis of increasing drug resistance among patients with multidrug-resistant or extensively drug-resistant tuberculosis undergoing treatment is poorly understood. Increasing drug resistance found among Mycobacterium tuberculosis recovered from cavitary isolates compared with paired sputum isolates suggests pulmonary cavities may play a role in the development of worsening tuberculosis drug resistance.