Conventional and real-time PCR targeting 16S ribosomal RNA for the detection of Mycobacterium tuberculosis complex.

Abstract

Conventional diagnostic methods for tuberculosis (TB) have limited sensitivity and specificity or are time-consuming. 16S rDNA and 16S rRNA of Mycobacterium tuberculosis complex (MTC) were used as targets to develop sensitive and specific polymerase chain reactions (PCRs) to improve the diagnosis of MTC. We developed conventional and real-time PCRs targeting 16S rDNA and rRNA of MTC. PCRs targeting 16S rRNA had a 10-100 times lower limit of detection for M. tuberculosis than PCRs targeting 16S rDNA. The sensitivities of the 16S rDNA PCR, 16S rRNA reverse transcription PCR (RT-PCR), 16S rDNA real-time PCR and 16S rRNA real-time RT-PCR for sputum specimens were respectively 92%, 94.6%, 96% and 100%. Real-time PCR showed no cross-reactivity, but conventional PCR had cross-reactivity to M. avium, M. gastri and M. nonchromogenicum. PCRs targeting the 16S rRNA of MTC were more sensitive than those targeting 16S rDNA; 16S rRNA real-time RT-PCR showed the highest sensitivity and specificity for MTC.