International Journal of Mycobacteriology (Jan 2023)

Use of light-emitting diode fluorescence microscopy to detect acid-fast bacilli in sputum as proficient alternative tool in the diagnosis of pulmonary tuberculosis in countries with limited resource settings

  • Gagni Coulibaly,
  • Antièmé Combo Georges Togo,
  • Anou Moise Somboro,
  • Mahamadou Kone,
  • Fah Gaoussou Traore,
  • Fatimata Diallo,
  • Boureima Degoga,
  • Amadou Somboro,
  • Hawa M'baye Dramé,
  • Moumine Sanogo,
  • Ousmane Kodio,
  • Bocar Baya,
  • Mohamed Tolofoudie,
  • Aminata Maiga,
  • Mamoudou Maiga,
  • Katy Saliba-Shaw,
  • Souleymane Diallo,
  • Seydou Doumbia,
  • Ibrahim Izetiégouma Maiga,
  • Fassé Samaké,
  • Bassirou Diarra

DOI
https://doi.org/10.4103/ijmy.ijmy_13_23
Journal volume & issue
Vol. 12, no. 2
pp. 144 – 150

Abstract

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Background: Despite recent advances in the development of more sensitive technologies for the diagnosis of tuberculosis (TB), in resource-limited settings, the diagnosis continues to rely on sputum smear microscopy. This is because smear microscopy is simple, cost-efficient and the most accessible tool for the diagnosis of TB. Our study evaluated the performance of light-emitting diode fluorescence microscopy (LED-FM) using auramine/rhodamine (auramine) and the fluorescein di-acetate (FDA) vital stain in the diagnostic of pulmonary TB in Bamako, Mali. Methods: Sputum smear microscopy was conducted using the FDA and auramine/rhodamine staining procedures on fresh samples using LED-FM to evaluate the Mycobacterium TB (MTB) metabolic activity and to predict contagiousness. Mycobacterial culture assay was utilized as a gold standard method. Results: Out of 1401 TB suspected patients, 1354 (96.65%) were retrieved from database, which were MTB complex culture positive, and 47 (3.40%) were culture negative (no mycobacterial growth observed). Out of the 1354 included patients, 1343 (95.86%), were acid-fast bacillus (AFB) positive after direct FDA staining, 1352 (96.50%) AFB positive after direct Auramine, and 1354 (96.65%) AFB positive with indirect auramine after digestion and centrifugation. Overall, the FDA staining method has a sensitivity of 98.82%, while the sensitivity of Auramine with direct observation was 99.48%, and 99.56% with the indirect examination. Conclusion: This study showed that, using fresh sputum both auramine/rhodamine and FDA are highly sensitive methods in diagnosing pulmonary TB and could be easily used in countries with limited resource settings.

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