Direct Molecular Characterization of Acid-Fast Bacilli Smear of Nontuberculosis Mycobacterium Species Causing Pulmonary Tuberculosis in Guna Yala Region, Panama

Am J Trop Med Hyg. 2021 Jul 8;105(3):633-637. doi: 10.4269/ajtmh.21-0096.


Mycobacterium tuberculosis (MTB) stands out as the main causative agent of pulmonary tuberculosis (TB). However, nontuberculous mycobacteria (NTM) species also have the potential to infect and cause TB in susceptible individuals. The objective of this study was to identify NTM species that cause public health problems in remote areas. The study was carried out using 105 sputum smears obtained from patients from the Guna Yala Region of Panama with clinical signs suggestive of TB. DNA was extracted from sputum smears. Nontuberculous mycobacteria and MTB were characterized using polymerase chain reaction restriction analysis (hsp65, rpob) and an evaluation of 24-mycobacterial interspersed repetitive units-variable number of tandem repeats loci. Twenty-six Mycobacterium species were characterized; 19 (18%) were identified as MTB, and 7 (6.7%) were identified as NTM (four M. avium complex, two M. haemophilum, one M. tusciae). These results suggest that at least one in five cases of pulmonary TB among this population is caused by an NTM. Thus, identifying the bacteria causing pulmonary disease is key even in remote regions of the world where standard diagnosis and culture are not available. Strengthening the laboratory capacity within the Guna Yala Region is needed to identify NTM infections promptly.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • DNA, Bacterial / chemistry
  • DNA, Bacterial / isolation & purification
  • Genotyping Techniques
  • Humans
  • Nontuberculous Mycobacteria / classification
  • Nontuberculous Mycobacteria / genetics*
  • Nontuberculous Mycobacteria / isolation & purification
  • Nontuberculous Mycobacteria / pathogenicity
  • Panama / epidemiology
  • Polymerase Chain Reaction
  • Sputum / microbiology
  • Tuberculosis, Pulmonary / epidemiology
  • Tuberculosis, Pulmonary / microbiology*


  • DNA, Bacterial