Title
Tuberculosis diagnosis and multidrug resistance testing by direct sputum culture in selective broth without decontamination or centrifugation
Date Issued
01 July 2008
Access level
open access
Resource Type
journal article
Author(s)
Grandjean L.
Martin L.
Herrera B.
Rivero M.
Escombe A.R.
Coleman D.
Mitchison D.
Publisher(s)
American Society for Microbiology
Abstract
Tuberculosis culture usually requires sputum decontamination and centrifugation to prevent cultures from being overgrown by contaminating bacteria and fungi. However, decontamination destroys many tuberculous bacilli, and centrifugation often is not possible in resource-poor settings. We therefore assessed the performance of Mycobacterium tuberculosis culture with unprocessed samples plated directly by using tuberculosisselective media and compared this procedure to conventional culture using centrifuge decontamination. Quadruplicate aliquots of strain H37RV were cultured in 7H9 broth with and without selective antimicrobials and after centrifuge decontamination. The subsequent comparison was made with 715 sputum samples. Split paired sputum samples were cultured conventionally with centrifuge decontamination and by direct culture in tuberculosis-selective media containing antibiotics. Centrifuge decontamination reduced tuberculosis H37RV colonies by 78% (P < 0.001), whereas direct culture in tuberculosis-selective media had no inhibitory effect. Similarly, in sputum cultures that were not overgrown by contaminants, conventional culture yielded fewer tuberculosis colonies than direct culture (P < 0.001). However, the sensitivity of conventional culture was greater than that of direct culture, because samples were less affected by contamination. Thus, of the 340 sputum samples that were tuberculosis culture positive, conventional culture detected 97%, whereas direct culture detected 81% (P < 0.001). Conventional and direct cultures both took a median of 8.0 days to diagnose tuberculosis (P = 0.8). In those direct cultures that detected drug resistance or susceptibility, there was a 97% agreement with the results of conventional culture (Kappa agreement statistic, 0.84; P < 0.001). Direct culture is a simple, low-technology, and rapid technique for diagnosing tuberculosis and determining drug susceptibility. Compared to that of conventional culture, direct culture has reduced sensitivity because of bacterial overgrowth, but in basic laboratories this deficit may be outweighed by the ease of use. Copyright © 2008, American Society for Microbiology. All Rights Reserved.
Start page
2339
End page
2344
Volume
46
Issue
7
Language
English
OCDE Knowledge area
Virología
Biología celular, Microbiología
Sistema respiratorio
Scopus EID
2-s2.0-49049095118
PubMed ID
Source
Journal of Clinical Microbiology
ISSN of the container
0095-1137
Sources of information:
Directorio de Producción Científica
Scopus