Abstract:

Objective To evaluate the detection performance of the fluorescent PCR probe melting curve (MeltPro) technique in detecting anti-tuberculosis drug resistance using smear-positive sputum specimens. Methods Sputum specimens from 500 sputum-positive tuberculosis patients in Xi’an Chest Hospital from September 2016 to August 2018 were collected. Sputum smear microscopy, GeneXpert MTB /RIF, BECTEC MGIT 960 liquid culture, phenotypic drug susceptibility test and MeltPro technique were applied to detect the drug resistance to rifampicin, isoniazid, second-line injection drugs and fluoroquinolones. Phenotypic drug susceptibility test was used as the reference standard to assess the detection performance. Results The sensitivity and specificity of MeltPro technique for rifampicin resistance detection were 98.7% (76/77) and 94.2% (343/364), for isoniazid were 82.3% (102/124) and 96.2% (304/316), for amikacin were 8/9 and 99.5% (432/434), for capreomycin were 6/7 and 99.1% (432/436), for levofloxacin were 90.6% (48/53) and 99.2% (386/389), and for moxifloxacin were 88.1% (37/42) and 96.5% (386/400), respectively. The sensitivity and specificity of GeneXpert MTB/RIF for detection of M.tuberculosis rifampicin resistance were 94.8% (73/77) and 94.0% (342/364), respectively. The results of both GeneXpert-MTB/RIF and MeltPro methods were well consistent with the phenotypic susceptibility test (Kappa values were 0.81 and 0.84, respectively), but the MeltPro method was more consistent. Conclusion MeltPro technique shows a good capability in detecting the drug resistance of anti-tuberculosis drugs of MTB including rifampicin, isoniazid, second-line injection drugs and fluoroquinolone using smear-positive sputum specimen.

Key words: Mycobacterium tuberculosis, Microbial sensitivity tests, Molecular probe techniques, Tuberculosis,multidrug-resistant, Sensitivity and specificity, Comparative study