Clinical evaluation of the polymerase chain reaction for the rapid diagnosis of tuberculosis

Abstract

Aims: Use of the polymerase chain reaction for the detection of Mycobacterium tuberculosis (TB PCR) as a basis for making clinical decisions on the initiation of antituberculosis treatment was studied. Methods: A retrospective study involving a cohort of 155 patients being investigated for tuberculosis in an infectious disease consultation service was undertaken. TB PCR was performed on pulmonary and extrapulmonary specimens from these patients. The sensitivity of TB PCR was analysed. Results: Of the 155 patients, 144 fitted the clinical diagnosis of tuberculosis, and 112 of them were culture positive for M tuberculosis. Sixty (58.3%) patients with clinical features suggestive of tuberculosis received antituberculosis treatment based on positive TB PCR alone. Of 224 clinical specimens (138 pulmonary and 86 extrapulmonary) sent for TB PCR, 148 (99 pulmonary and 49 extrapulmonary) were positive in 117 patients. Of the 690 clinical specimens sent for culture, 279 were positive for M tuberculosis in 112 patients. The diagnostic sensitivity of TB PCR was 75.9% (85 of 112) and 81.3% (117 of 144) in patients with culture confirmed and clinically diagnosed tuberculosis, respectively. Using culture as the gold standard, the overall sensitivity of TB PCR was 78.3%, and for pulmonary and extrapulmonary specimens it was 82.3% and 72.0%, respectively. Conclusions: TB PCR is a rapid and reliable test in the diagnosis and management of tuberculosis.

Evaluating bacterial pathogen DNA preservation in museum osteological collections

“…55-75%: Haas et al 2000;Zink et al 2001a;Fletcher et al 2003;Zink et al 2003). These latter data compare favourably with published rates of detection using simple PCR-based systems on modern, diagnosed, clinical samples, which are around 80% (Portillo-Gomez et al 2000;Van der Spoel van Dijk et al 2000;Mitarai et al 2001;Narayanan et al 2001;Alfonso et al 2002;Yee et al 2002;Leung et al 2003;Cheng et al 2004), and higher than detection rates for blood (40%: Taci et al 2003), urine (56%: Kafwabulula et al 2002), and host DNA in studies of animal bones from temperate archaeological sites (around 10-20%: Haynes et al 2002;Edwards et al 2004). The high frequency of amplification success from archaeological samples has been attributed to the enhanced stability of the M. tuberculosis cell wall (Donoghue et al 2004).…”

The role of polymerase chain reaction in the management of osteoarticular tuberculosis

“…Most extrapulmonary specimens do not have a large concentration of bacilli. In addition, the culture of M. tuberculosis is time consuming, taking 6-8 weeks for the growth to appear [5]. So, mostly, the diagnosis of tuberculosis depends on histological evidence, which may also sometimes be inconclusive, in addition to the need for high levels of expertise.…”

“…Conventional microbiological methods like Ziehl-Neelson staining (Z-N smear) for acid fast bacilli (AFB) and culture of Mycobacterium tuberculosis on Lowenstein Jensen media (L-J) have much lower sensitivity and specificity because of the paucibacillary nature of extrapulmonary tuberculosis [10,24]. Also, for a positive AFB smear, 5,000-10,000 bacilli per mL are needed [5]. Most extrapulmonary specimens do not have a large concentration of bacilli.…”

Evaluation of rapid GeneXpert MTB/RIF method using DNA tissue specimens of vertebral bones in patients with suspected spondylitis TB

“…19 Various studies observed the results of PCR technique to diagnose extrapulmonary TB. 8,20 Currently, various PCR studies have developed into GeneXpert MTB/RIF method using heminested real-time polymerase chain reaction (PCR) assay. 11,17,21 This system works automatically toward the lysis of bacteria, extraction of the DNA, amplifications, and the detection of amplicon in a single system using a rapid approach.…”