Within-host pathogen population diversity predicts treatment response in tuberculosis

A study followed 364 patients with newly diagnosed rifampicin-susceptible tuberculosis in South Africa over two years. Researchers found that genetic diversity of Mycobacterium tuberculosis bacteria within the patient's body at diagnosis is a strong independent predictor of unfavorable treatment outcomes. Patients with more than 3 genetic variants had double the risk of treatment failure, death, or relapse. Genetic variants were found primarily in genes related to pathogen adaptation and drug resistance. The number of genetic variants ranged from 0 to 20, with a median of 1 per patient. The results suggest that measuring bacterial genetic diversity could help identify patients at higher risk of treatment failure and allow individualized treatment duration adjustment.