Liquid vs. solid culture for tuberculosis: performance and cost in a resource-constrained setting

Int J Tuberc Lung Dis. 2010 Aug;14(8):1024-31.


Setting: National Health Laboratory Services tuberculosis (TB) laboratory, South Africa.

Objectives: To compare Mycobacterium Growth Indicator Tube (MGIT) with Löwenstein-Jensen (LJ) medium with regard to Mycobacterium tuberculosis yield, time to positive culture and contamination, and to assess MGIT cost-effectiveness.

Design: Sputum from gold miners was cultured on MGIT and LJ. We estimated cost per culture, and, for smear-negative samples, incremental cost per additional M. tuberculosis gained with MGIT using a decision-tree model.

Results: Among 1267 specimens, MGIT vs. LJ gave a higher yield of mycobacteria (29.7% vs. 22.8%), higher contamination (16.7% vs. 9.3%) and shorter time to positive culture (median 14 vs. 25 days for smear-negative specimens). Among smear-negative samples that were culture-positive on MGIT but negative/contaminated on LJ, 77.3% were non-tuberculous mycobacteria (NTM). Cost per culture on LJ, MGIT and MGIT+LJ was respectively US$12.35, US$16.62 and US$19.29. The incremental cost per additional M. tuberculosis identified by standard biochemical tests and microscopic cording was respectively US$504.08 and US$328.10 using MGIT vs. LJ, or US$160.80 and US$$109.07 using MGIT+LJ vs. LJ alone.

Conclusion: MGIT gives higher yield and faster results at relatively high cost. The high proportion of NTM underscores the need for rapid speciation tests. Minimising contaminated cultures is key to cost-effectiveness.

Publication types

  • Comparative Study

MeSH terms

  • Adult
  • Aged
  • Bacteriological Techniques / economics*
  • Bacteriological Techniques / standards*
  • Costs and Cost Analysis
  • Culture Media / economics
  • Culture Media / standards*
  • Follow-Up Studies
  • Humans
  • Middle Aged
  • Mycobacterium fortuitum / growth & development
  • Mycobacterium fortuitum / isolation & purification*
  • Prevalence
  • Reproducibility of Results
  • Retrospective Studies
  • South Africa / epidemiology
  • Sputum / microbiology*
  • Tuberculosis / diagnosis*
  • Tuberculosis / epidemiology
  • Tuberculosis / microbiology
  • Young Adult


  • Culture Media