Display Settings:

Format

Send to:

Choose Destination
See comment in PubMed Commons below
N Engl J Med. 2006 Oct 12;355(15):1539-50.

Microscopic-observation drug-susceptibility assay for the diagnosis of TB.

Author information

  • 1Department of Infectious Diseases and Immunity and the Wellcome Centre for Clinical Tropical Medicine, Imperial College London, Faculty of Medicine (Hammersmith Campus), London, United Kingdom. davidajmoore@msn.com

Abstract

BACKGROUND:

New diagnostic tools are urgently needed to interrupt the transmission of tuberculosis and multidrug-resistant tuberculosis. Rapid, sensitive detection of tuberculosis and multidrug-resistant tuberculosis in sputum has been demonstrated in proof-of-principle studies of the microscopic-observation drug-susceptibility (MODS) assay, in which broth cultures are examined microscopically to detect characteristic growth.

METHODS:

In an operational setting in Peru, we investigated the performance of the MODS assay for culture and drug-susceptibility testing in three target groups: unselected patients with suspected tuberculosis, prescreened patients at high risk for tuberculosis or multidrug-resistant tuberculosis, and unselected hospitalized patients infected with the human immunodeficiency virus. We compared the MODS assay head-to-head with two reference methods: automated mycobacterial culture and culture on Löwenstein-Jensen medium with the proportion method.

RESULTS:

Of 3760 sputum samples, 401 (10.7%) yielded cultures positive for Mycobacterium tuberculosis. Sensitivity of detection was 97.8% for MODS culture, 89.0% for automated mycobacterial culture, and 84.0% for Löwenstein-Jensen culture (P<0.001); the median time to culture positivity was 7 days, 13 days, and 26 days, respectively (P<0.001), and the median time to the results of susceptibility tests was 7 days, 22 days, and 68 days, respectively. The incremental benefit of a second MODS culture was minimal, particularly in patients at high risk for tuberculosis or multidrug-resistant tuberculosis. Agreement between MODS and the reference standard for susceptibility was 100% for rifampin, 97% for isoniazid, 99% for rifampin and isoniazid (combined results for multidrug resistance), 95% for ethambutol, and 92% for streptomycin (kappa values, 1.0, 0.89, 0.93, 0.71, and 0.72, respectively).

CONCLUSIONS:

A single MODS culture of a sputum sample offers more rapid and sensitive detection of tuberculosis and multidrug-resistant tuberculosis than the existing gold-standard methods used.

Copyright 2006 Massachusetts Medical Society.

Comment in

PMID:
17035648
[PubMed - indexed for MEDLINE]
PMCID:
PMC1780278
Free PMC Article

Images from this publication.See all images (3)Free text

Figure 1
Figure 2
Figure 3
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for Atypon Icon for PubMed Central
    Loading ...
    Write to the Help Desk