Author/Authors :
Sheikholslami، Maryam Fatemeh نويسنده Mycobacteriology Research Center, NRITLD, Shaheed Beheshti University of Medical Science.Tehran, I.R.Iran. Sheikholslami, Maryam Fatemeh , Farnia، Parissa نويسنده , , Tabarsi، Payam نويسنده , , Aghali Merza، Mouayad نويسنده Mycobacteriology Research Center, NRITLD, Shaheed Beheshti University of Medical Science.Tehran, I.R.Iran. Aghali Merza, Mouayad , Valiollah Pour Amiri، Majid نويسنده , , Mohammadi، Forozan نويسنده , , Aghaii، Seyed Mohammad Bagher نويسنده Molecular Pathology Aghaii, Seyed Mohammad Bagher , Kazempour Dizaji، Mehdi نويسنده Mycobacteriology Research Center, National Research Institute of Tuberculosis and Lung Diseases (NRITLD), Shahid Beheshti University of Medical Scienc , , Masjedi، Mohammad-Reza نويسنده , , Velayati، Ali Akbar نويسنده National Research Institute of Tuberculosis and Lung Disease (NRITLD), Shahid Beheshti University of Medical Science. I.R.Iran Velayati, Ali Akbar
Abstract :
Objectives:
Advancements in molecular technology increased our understanding of genetic mechanism of drug
resistance. Nowadays, the chance of rapid detection of resistant Mycobacterium tuberculosis (M. tuberculosis) strains is increased. In the present study, we aimed to investigate the sensitivity and specificity of PCR-SSCP for detecting
susceptible and resistant strains of M. tuberculosis compared with DNA sequencing.
Patients and Methods:
To calculate the sensitivity and specificity of PCR-SSCP assay to detect drug resistance in M.
tuberculosis, respiratory samples were collected from suspected patients referred to Mycobacteriology Research Center
(Masieh Daneshvary Hosptial) since 2002. Susceptibility testing against first line drugs was performed on 74 culturepositivespecimens. Consequently, PCR-SSCP and DNA sequencing were performed on katG, inhA, ahpC and rpoB
genes.
Results:
Drug-susceptibility testing by the proportional method in selected samples revealed 16 MDR (21.6%), 23
mono-drug resistant (31%) and 35 susceptible strains (47.3%). In comparison with DNA sequencing as a gold standard
for molecular methods, the sensitivity of PCR-SSCP assay for detecting of mutation in 315 codon of katG gene was
94.74% (CI=73.97%-99.87%) with 100% (CI=93.51%-100%) specificity. In contrast, the sensitivity and specificity of
this assay in detecting of rpoB gene were 70.8 (CI=48.91%-87.38%) and 88 (CI=75.69%-95.47%), respectively.
Conclusion:
PCR-SSCP in combination with DNA sequencing can be used as screening method to detect MDR-TB and
mono-drug resistant cases.
