bedaquiline and Granuloma

Drug-resistant tuberculosis (DR-TB) continues to pose a threat to the global eradication of TB. Regimens for extensively drug-resistant (XDR) TB are lengthy and poorly tolerated, often with unsuccessful outcomes. The TB Alliance Nix-TB trial investigated the safety and efficacy of a 26-week regimen of bedaquiline, pretomanid and linezolid (BPaL) in participants with XDR-TB, multidrug-resistant (MDR) TB treatment failure or intolerance. In this trial 9 out of 10 participants were cured. We describe a trial participant with XDR-TB who presented with new-onset seizures soon after BPaL treatment completion. Imaging showed a right temporal ring-enhancing lesion, and a sterile tuberculous granuloma was confirmed after a diagnostic, excisional biopsy. Learning points include management of a participant with a tuberculoma after BPaL completion, efficacy of new medications for central nervous system (CNS) TB and a review of their CNS penetration. This is the first case of pretomanid use in CNS TB.

Topics: Antitubercular Agents; Diarylquinolines; Extensively Drug-Resistant Tuberculosis; Granuloma; Humans; Linezolid; Nitroimidazoles; Treatment Outcome; Tuberculosis, Multidrug-Resistant

The lengthy chemotherapy of tuberculosis reflects the ability of a small subpopulation of Mycobacterium tuberculosis bacteria to persist in infected individuals. To date, the exact location of these persisting bacteria is not known. Lung lesions in guinea pigs infected with M. tuberculosis have striking similarities, such as necrosis, mineralization, and hypoxia, to natural infections in humans. Guinea pigs develop necrotic primary lesions after aerosol infection that differ in their morphology compared to secondary lesions resulting from hematogenous dissemination. In infected guinea pigs conventional therapy for tuberculosis during 6 weeks reduced the bacterial load by 1.7 logs in the lungs and, although this completely reversed lung inflammation associated with secondary lesions, the primary granulomas remained largely unaffected. Treatment of animals with the experimental drug R207910 (TMC207) for 6 weeks was highly effective with almost complete eradication of the bacteria throughout both the primary and the secondary lesions. Most importantly, the few remnants of acid-fast bacilli remaining after R207910 treatment were to be found extracellular, in a microenvironment of residual primary lesion necrosis with incomplete dystrophic calcification. This zone of the primary granuloma is hypoxic and is morphologically similar to what has been described for human lung lesions. These results show that this acellular rim may, therefore, be a primary location of persisting bacilli withstanding drug treatment.

Topics: Animals; Antibiotics, Antitubercular; Antitubercular Agents; Colony Count, Microbial; Diarylquinolines; Female; Granuloma; Guinea Pigs; Hypoxia; Isoniazid; Lung; Mycobacterium tuberculosis; Nitroimidazoles; Pyrazinamide; Quinolines; Radiation-Sensitizing Agents; Rifampin; Spleen; Tuberculosis