Objective/background: The aim of this study was to analyze the detection of nontuberculous mycobacterial (NTM) species derived from sputum specimens of pulmonary tuberculosis (TB) suspects. Increasing prevalence and incidence of pulmonary infection by NTM species have widely been reported in several countries with geographical variation.
Materials and methods: Between January 2014 and September 2015, sputum specimens from chronic pulmonary TB suspect patients were analyzed. Laboratory examination of mycobacteria was conducted in the TB laboratory, Department of Clinical Microbiology, Dr. Soetomo Hospital, Surabaya. Detection and identification of mycobacteria were performed by the standard culture method using the BACTEC MGIT 960 system (BD) and Lowenstein-Jensen medium. Identification of positive Mycobacterium tuberculosis complex (MTBC) was based on positive acid-fast bacilli microscopic smear, positive niacin accumulation, and positive TB Ag MPT 64 test results (SD Bioline). If the growth of positive cultures and acid-fast bacilli microscopic smear was positive, but niacin accumulation and TB Ag MPT 64 (SD Bioline) results were negative, then the isolates were categorized as NTM species. MTBC isolates were also tested for their sensitivity toward first-line anti-TB drugs, using isoniazid, rifampin, ethambutol, and streptomycin.
Results: From 2440 sputum specimens of pulmonary TB suspect patients, 459 isolates (18.81%) were detected as MTBC and 141 (5.78%) as NTM species.
Conclusion: From the analyzed sputum specimens, 18.81% were detected as MTBC and 5.78% as NTM species. Each pulmonary TB suspect patient needed clinical settings to suspect causative agents of MTBC and/or NTM species; clinicians have to understand the local epidemiological data for the evaluation of causes of lung infection to determine appropriate therapy.