Clinical and Microbiological Insights into Non-Tuberculous Mycobacteria: A Study from a Tertiary Care Centre in Central India

Introduction: The prevalence of non-tuberculous mycobacteria (NTM) infection is increasing worldwide, presenting challenges for clinicians and microbiologists alike. This emerging infection is becoming more common in developed countries. While the clinical presentation of Mycobacterium tuberculosis complex (MTBC) and NTM may resemble each other, their treatment regimens differ significantly. The aim of this study is to comprehensively investigate and characterize the clinical and microbiological aspects of NTM in presenting presumption TB cases attending tertiary care center in central India. Methods: A total of 970 suspected tuberculosis (TB) cases, comprising 512 pulmonary (52.7%) and 458 extrapulmonary (47.3%) cases, were included in this study. Data encompassing clinical, laboratory, and radiological findings were recorded. NTM diseases were verified using the criteria set forth by the American Thoracic Society/Infectious Diseases Society of America. All samples underwent Ziehl- and Neelsen staining, NALC-NaOH decontamination method for cultivation in the MGIT-960 system (Becton Dickinson Diagnostic Instrument Systems). Final identification and differentiation between Mycobacterium tuberculosis complex (MTBC) and various NTM species were confirmed through the GenoType Mycobacterium CM/AS assay. Results: Among the 970 samples tested, 37 cases (3.8%) tested positive for acid-fast bacilli (AFB) via Ziehl-Neelsen (ZN) staining, and 160 cases (16.5%) showed positive mycobacterial cultures. Of these, 20 out of 160 cases (12.5%) were confirmed as non-tuberculous mycobacteria (NTM) using the GenoType Mycobacterium CM assay. Among the NTM isolates, 75% (15 cases) originated from pulmonary sources. In pulmonary NTM cases, the most commonly observed species were M. fortuitum, M. abscessus, and M. senegalens. Discussion: The study highlights a significant presence of NTM in presumed TB cases, emphasizing the necessity for differential diagnosis to ensure appropriate treatment. The findings underline the importance of incorporating advanced diagnostic tools, such as the GenoType Mycobacterium CM/AS assay, into routine practice. This will facilitate timely and accurate identification of NTM, improving patient outcomes. Conclusion: The predominant isolation of and M. fortuitum and M. abscessus as the most prevalent NTM, particularly among males in the 30-50 age group from pulmonary sources, has been observed in tertiary care centers in central India.