Evaluation of ku gene as a differential biomarker for rapid molecular detection of Mycobacterium tuberculosis complex using a real-time PCR assay

Purpose: currently TB diagnosis is limited by some major limitations in low-income and less experienced hospitals. Recently, it has been proposed that the ku gene of mycobacterial strains has the potential to be a highly specific and sensitive candidate biomarker for molecular detection of Mycobacterium tuberculosis (Mtb). This study was aimed to evaluate the specificity and sensitivity of a real-time PCR assay for detection of ku gene in Mtb complex to determine its applicability for Mtb identification. Materials and methods: The identification of Mtb was confirmed using GeneXpert assay. Specific primers for ku gene were designed and the cycle threshold (Ct) value from the real-time PCR was used as a proxy measure of the cut-off point. Receiver operating characteristic (ROC) curve analysis was conducted to determine the diagnostic performance of ku gene in detecting Mtb directly from clinical specimens. Results: ku amplification was interpreted as positive and negative based on Ct values, in which a value <۳۸ was considered positive and a value >۴۰ was considered negative. Our findings revealed that the ku gene was found to be distributed in all Mtb-positive samples. Of note, none of the Mtb-negative exhibited a specific signal in a maximum of ۴۰ cycles. Conclusions: The ku gene amplification using real-time PCR indicated high sensitivity and specificity for the detection of Mtb complex in sputum samples.

کلیدواژه ها:

Mycobacterium tuberculosis ، ku gene ، biomarker ، nucleic acid amplification tests (NAATs) ، GeneXpert MTB/RIF