Early and rapid microscopy-based diagnosis of true treatment failure and MDR-TB

Int J Tuberc Lung Dis. 2006 Nov;10(11):1248-54.

Abstract

Setting: Damien Foundation tuberculosis (TB) control project in Bangladesh.

Objective: Early diagnosis of true TB treatment failure and multidrug resistance (MDR) for more efficient DOTS-Plus.

Design: Prospective comparison of performance on smear-positive sputum of fluorescein diacetate (FDA) vital staining vs. culture, and of slide drug susceptibility testing (slide DST) vs. the Löwenstein-Jensen (LJ) proportion method.

Results: FDA reached 92% positive and 97% negative predictive value directly on fresh sputum, but only 94% and 62%, respectively, on transported smears. Accuracy on washed cetylpyridinium chloride transported sputum was similar to that on fresh sputum. Slide DST on fresh smear-positive sputum failed less often than LJ DST, with 96% accurate results for rifampicin and MDR-TB diagnosis. Good results were obtained for isoniazid (90% accuracy), but not for ethambutol or streptomycin.

Conclusions: We can confirm that FDA staining allows rapid screening for viable acid-fast bacilli and true treatment failure in delayed smear converters or smear-defined failures, while slide DST assures fast and accurate confirmation of MDR-TB in selected populations. The tests can be applied safely in resource-poor settings. Their successive use could be an efficient strategy for screening and an early start on standardised regimens of DOTS-Plus candidates.

MeSH terms

  • Antitubercular Agents / therapeutic use*
  • Colony Count, Microbial
  • Diagnosis, Differential
  • Humans
  • Mycobacterium tuberculosis / isolation & purification*
  • Prospective Studies
  • Reproducibility of Results
  • Sputum / microbiology*
  • Time Factors
  • Treatment Failure
  • Tuberculosis, Multidrug-Resistant / diagnosis*
  • Tuberculosis, Multidrug-Resistant / drug therapy*
  • Tuberculosis, Multidrug-Resistant / microbiology
  • Tuberculosis, Pulmonary / diagnosis*
  • Tuberculosis, Pulmonary / drug therapy*
  • Tuberculosis, Pulmonary / microbiology

Substances

  • Antitubercular Agents