Rapid diagnosis of tuberculous pleuritis by real-time PCR

Abstract number: 1733_1483

Baba K., Pathak S., Sviland L., Dyrhol-Riise A.M., Langeland N., Hoosen A.A., Asjø B., Mustafa T.

Tuberculosis is a public health problem. The hallmark of tuberculosis control is prompt diagnosis and treatment. This is even more important in suspected tuberculosis pleuritis (TP) for which accurate diagnosis is very crucial since delay in chemotherapeutic intervention is associated with poor prognosis. Diagnosis of TP requires microscopy and culture both of which has limitation, microscopy is not sensitive and culture takes time. The nested PCR (N-PCR) is used to detect M. tuberculosis complex organisms and genus specific real time PCR is used for detection of a broader spectrum of mycobacteria since atypical mycobacteria is common in HIV-TB coinfected patients. The real-time PCR (RT-PCR) has the advantage of not being prone to contamination and quicker because it does not require post amplification detection.

The aim of this study was to assess the diagnostic potential of nested PCR of the IS6110 gene to detect M. tuberculosis complex organisms and of RT-PCR for genus specific hsp65 detection in the diagnosis of TP.

Thirty-six paraffin-embedded pleural tissue samples were taken from the archives of the department of Pathology Dr. George Mukhari Hospital/Medunsa Campus University of Limpopo Pretoria South Africa. Twenty-five biopsies were from patients with clinical TP, and 11 biopsies from cases with other diseases were used as controls.

Nested PCR was performed using the Mycobacterium tuberculosis complex specific IS6110 primer and real-time PCR was performed using the genus specific hsp65 primer (ABI 7500 RT-PCR system).

Sixteen samples were positive by N-PCR and 15/16 was positive by RT-PCR. Out of the 11 non-TB cases 2 were positive by both N-PCR and RT-PCR while additional 2 cases were positive by only RT-PCR. Using clinical diagnosis as gold standard the sensitivity of N-PCR and RT-PCR were 64% and 76% while specificity was 82% and 64%, respectively. The sensitivity of RT-PCR using N-PCR as gold standard was 94%.

This study showed that RT-PCR is equally sensitive to N-PCR in diagnosing TP. Its lower specificity might be due to presence of atypical mycobacteria. Therefore RT-PCR is highly sensitive, not prone to contamination, and its quicker turn around time will lead to rapid diagnosis of TP.

Session Details

Date: 31/03/2007
Time: 00:00-00:00
Session name: European Society of Clinical Microbiology and Infectious Diseases
Location: ICC, Munich, Germany
Presentation type:
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