Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2012 May;135(5):778-82.

Detection of Mycobacterium tuberculosis directly from sputum specimens & phenotypic drug resistance pattern of M. tuberculosis isolates from suspected tuberculosis patients in Chennai

K Lily Therese  1 , R Gayathri, L Dhanurekha, R Sridhar, N Meenakshi, H N Madhavan, S Edwin Manoj, A Kamala Vinayagam
Affiliations

Detection of Mycobacterium tuberculosis directly from sputum specimens & phenotypic drug resistance pattern of M. tuberculosis isolates from suspected tuberculosis patients in Chennai

K Lily Therese et al. Indian J Med Res. 2012 May.

Abstract

Background & objectives: mRNA is more rapidly destroyed in cells than rRNA or genomic DNA, an assay targeting bacterial mRNA would provide a better guide to mycobacterial viability than amplification tests directed at DNA or rRNA targets. This study was carried out to standardize reverse transcriptase PCR (RT-PCR) targeting 85B gene for the rapid detection of viable Mycobacterium tuberculosis from sputum specimens of suspected TB patients at Chennai, South India and to detect MDR-TB circulating in this population.

Methods: Sputum samples from clinically suspected tuberculosis patients (n=301) and 78 controls were included in the study. The sputum samples were collected in sterile diethyl pyrocarbonate (DEPC) treated containers and transported in ice to the laboratory within 2 h to prevent degradation of RNA. RT-PCR targeting 85B gene, mycobacterial culture and phenotypic drug susceptibility testing for the first line drugs streptomycin (S), isoniazid (H), rifampicin (R), ethambutol (E) and pyrazinamide (Z) were performed by BACTEC microMGIT culture system for all the sputum specimens.

Results: All the 78 controls were negative for culture and RT-PCR. Among the 301 sputum specimens from patients, 231 (76.8%) were RT-PCR positive and 70 (23.2%) were negative. There were 166 M. tuberculosis isolates, of which 11 (2.9%) were MDR-TB, 33 (8.7%) were polyresistant, 31 (8.2%) were monoresistant and 91 (30.2%) were sensitive to all five first line anti-tuberculous drugs by phenotypic drug susceptibility testing. Monoresistance was higher with Z [20 (20.8%)], followed by S [6 (3%)].

Interpretation & conclusions: RT-PCR targeting 85B gene of M. tuberculosis was a specific, rapid, reliable technique to detect the M. tuberculosis directly from sputum specimens. Our results showed that 2.9 per cent of M. tuberculosis isolates in the study population of Chennai were MDR.

PubMed Disclaimer

References

    1. Global tuberculosis control - surveillance, planning, financing. WHO Report 2008 WHO/HTM/TB/2008.393. Available from: http://www.who.int/tb/publications/global_report/2008/en/index.html .
    1. Yoneda M, Fukui Y, Yamanouchi T. Extracellular proteins of tubercle bacilli. V. Distribution of alpha and beta antigens in various mycobacteria. Biken J. 1965;8:201–3. - PubMed
    1. Wiker HG, Harboe M, Lea TE. Purification and characterization of two protein antigens from the heterogeneous BCG85 complex in Mycobacterium bovis BCG. Int Arch Allergy Appl Immunol. 1986;81:298–306. - PubMed
    1. Salata RA, Sanson AJ, Malhotra IJ, Wiker HG, Harboe M, Phillips NB, et al. Purification and characterization of the 30,000 dalton native antigen of Mycobacterium tuberculosis and characterization of six monoclonal antibodies reactive with a major epitope of this antigen. J Lab Clin Med. 1991;118:589–98. - PubMed
    1. Desjardin LE, Perkins MD, Teixeira L, Perkins MD, Cave MD, Eisenach KD. Alkaline decontamination of sputum specimens adversely affects stability of mycobacterial mRNA. J Clin Microbiol. 1996;34:2435–9. - PMC - PubMed

Publication types

MeSH terms