Modified gold nanoparticle colorimetric probe-based biosensor coupled with allele-specific PCR for rapid detection of G944C mutation associated with isoniazid resistance

Aim and Background: The emergence of multidrug-resistant (MDR) strains of Mycobacterium tuberculosis (MTB) makes tuberculosis (TB) difficult to control and treat. Therefore, rapid and reliable detection of MDR-TB within the community plays a significant role. The aim of this study was to investigate the use of modified gold nanoparticle (AuNP) colorimetric probe-based biosensor coupled with allele-specific PCR for the rapid detection of G944C mutation associated with isoniazid resistance in MTB. Methods: Based on the citrate reduction method, the AuNPs were synthesized and functionalized using thiol-modified oligonucleotides (AuNP-biosensor). The AuNP-biosensor method was compared to the gold standard in terms of analytical and clinical sensitivity and specificity, positive predictive value (PPV), negative predictive value (NPV), diagnostic odds ratio (DOR), and accuracy. The gold standard was defined as a positive result in sequencing. Results and discussion: The AuNP-biosensor had 100% sensitivity and specificity for detection of G944C mutation. After allele-specific PCR amplification the results were carried out for less than 15 min with ready-to-use AuNP-biosensor. PPV, NPV, DOR and accuracy of this method were 100%, 100%, 309 and 100%, respectively. Conclusion: The method designed in this study can identify the desired mutation with high efficiency after initial amplification, either from the sputum sample or from isolated bacteria. By designing a panel of this method, different MTB resistance-associated mutations could be detected more rapidly.