Profile of patients with pulmonary non-tuberculous mycobacterial disease mimicking pulmonary tuberculosis.

INTRODUCTION: With the introduction of newer molecular diagnostic tools, an increasing number of Non-tuberculous Mycobacteria (NTM) affecting the respiratory system and mimicking symptoms of pulmonary tuberculosis (PTB) are being identified. They may be misdiagnosed and treated as PTB, often categorized as treatment failures if they do not respond to treatment. This manuscript aims to characterize patients with pulmonary NTM disease. METHODS: Patient characteristics of bacteriologically confirmed pulmonary NTM disease, attending the ICMR-National Institute for Research in Tuberculosis, Chennai were prospectively compiled over a two-year period (2017-2018). RESULTS: A total of 122 patients with recurrent chest symptoms and not responding to anti-tuberculosis treatment were screened for NTM. Thirty-nine cases (26 males and 13 females) of symptomatic pulmonary NTM were diagnosed. The mean (SD) patient age and body mass index were 48.6 ± 11 years and 16.3 ± 3. All male participants were smokers, had at least one episode of previous ATT. Mycobacterium kansasii (48.7%) was the most frequently isolated species followed by Mycobacterium intracellulare (20.5%), Mycobacterium abscessus (7.6%) followed by Mycobacterium avium, Mycobacterium fortuitum, Mycobacterium kyorinense, and Mycobacterium simiae. Infection with multiple NTMs was seen in four patients. Isoniazid resistance was identified in 20 patients. Based on species identified, treatment was initiated as per American Thoracic Society guidelines and continued up to 12 months of culture negativity. CONCLUSIONS: M. kansasii is the commonest pulmonary NTM isolated in Tamilnadu with a higher prevalence in males and elderly. Sensitization of both patients and providers is essential to avoid misdiagnosis and delay in diagnosis of pulmonary NTM disease as pulmonary TB.

Quality indicators in a mycobacteriology laboratory supporting clinical trials for pulmonary tuberculosis.

BACKGROUND: Documentation of structured quality indicators for mycobacteriology laboratories supporting exclusively controlled clinical trials in pulmonary tuberculosis (PTB) is lacking. OBJECTIVE: To document laboratory indicators for a solid (Lowenstein-Jensen medium) culture system in a mycobacteriology laboratory for a period of 4years (2007-2010). METHODS: The sputum samples, collected from PTB suspects/patients enrolled in clinical trials, were subjected to fluorescence microscopy, culture and drug sensitivity testing (DST). Data was retrospectively collected from TB laboratory registers and computed using pre-formulated Microsoft Office Excel. Laboratory indicators were calculated and analyzed. RESULTS: The number of samples processed in a calendar year varied from 6261 to 10,710. Of the samples processed in a calendar year, specimen contamination (4.8-6.9%), culture positives (78.4-85.1%) among smear positives, smear positives (71.8-79.0%) among culture positive samples, smear negatives among culture negative samples (95.2-96.7%), and average time to report DST results (76-97days) varied as shown in parentheses. CONCLUSION: Values of quality indicators in mycobacteriology laboratories supporting exclusively clinical trials of PTB have to be defined and used for meaningful monitoring of laboratories.