Detection of Mycobacterium tuberculosis growth by direct microscopic observation has a lower cost, higher sensitivity and higher diagnostic value than liquid and solid media cultures

Indian J Med Microbiol. 2014 Jul-Sep;32(3):315-7. doi: 10.4103/0255-0857.136585.

Abstract

Background: Culture is needed to confirm tuberculosis but results are generally obtained after several weeks.

Objectives: We compared a direct microscopic observation technique for detection of mycobacterial culture positivity (MODS) with the classic solid and MB/BacT cultures in terms of sensitivity, contamination rate, speed and cost on 488 samples.

Results: The sensitivity of the MODS technique--99,2% (162 positive samples) was higher than MB/BacT 78,4% (125 positive samples) and solid culture 69,6% (113 positive samples) P<0.005 for all comparisons. The median times to positivity were 21, 13.3 and 3 days on solid media, B/BacT and MODS respectively.

Conclusions: The MODS technique is faster and more sensitive than both solid media and MB/BacT culture.

Publication types

  • Comparative Study
  • Evaluation Study

MeSH terms

  • Bacteriological Techniques / methods*
  • Costs and Cost Analysis
  • Diagnostic Tests, Routine / methods*
  • Humans
  • Microscopy / methods*
  • Mycobacterium tuberculosis / growth & development
  • Mycobacterium tuberculosis / isolation & purification*
  • Sensitivity and Specificity
  • Time Factors
  • Tuberculosis / diagnosis*
  • Tuberculosis / microbiology