Diagnosis and treatment of patients with pulmonary nontuberculous mycobacterial diseases in Arkhangelsk, Russia

Background Nontuberculous mycobacteria (NTM) are acid-fast bacilli (AFB) that can cause disease in human. Patients with NTM pulmonary disease can be falsely diagnosed with pulmonary tuberculosis (TB) due detection of AFB in sputum and similar clinical and chest X-ray picture. Laboratory detection of NTM is complicated and does not always mean presence of the disease, but can be attributed to colonization or sample contamination. Molecular tests, such as Genotype Mycobacterium CM/AS, allow quick and reliable detection of NTM. Objective To assess the NTM identification rate, to estimate the incidence of pulmonary NTM disease and to report the treatment outcomes among patients with NTM disease. Design Retrospective cohort design. Results NTM were detected among 92 (0.98 per 100,000 population) presumptive pulmonary TB patients in Arkhangelsk region in 2010-2017 among who 39 (0.42 per 100,000 population) patients were diagnosed with NTM disease. The most prevalent species found in our study were M. avium (33%) and M.intracellulare (11%). 69% of patients with NTM disease completed their treatment, 15% died, 13% were lost to follow up and 3% failed treatment. Conclusion A system of diagnostics and treatment for NTM disease was set up in the Arkhangelsk region in Russia. Average NTM identification rate and incidence of pulmonary NTM disease were 0.98 per 100,000 and 0.42 per 100,000 population accordingly and were lower than reported in other studies. Treatment success rate in our study was 69% encouraging further improvements in diagnostics and treatment of patients with NTM.