Haider H. Mitab¹, Abir Muhssan Jabar Al Zaydi
Multidrug-resistant tuberculosis (MDR-TB) is a global problem that many countries are challenged with. Rapid and accurate detection of MDR-TB is critical for appropriate treatment and controlling of TB. The aims is detection of multidrug-resistant Tuberculosis from cultured samples by using Polymerase Chain Reaction. A total of 30 M. tuberculosis isolates from cases with diagnosed TB by GeneXpert, AFB and Culture on L. J media after incubation period from 3-8 weeks, DNA extraction from bacteria colonies. Resistant isolates were tested for characterization of mutations in the rpoB, KatG InhA1 and IhA2 genes by Real Time PCR. The results of the real time PCR showed that mutations of genes (rpoB, katG, inhA1 and inhA2) that were responsible for resistance to rifampicin and isoniazid. The test showed positive results for resistance genes (20%, 10%, 6.6%, 10% Respectively) as well as note that the values of Ct for this test ranged from (12-38.25), and the melting points of the genes were between (85-88.5 Co). Real time PCR results identified three mutations of MDR (rifampicin and isoniazide) resistance genes, whereas there was one MDR mutation of molecular diagnostic results with the GeneXpertMTB/RIF test for rifampicin. When comparing the results of the Real time PCR and GeneXpert tests at the level of the genetic mutation with rifampicin, the real time PCR test showed four resistance mutations for the rpoB gene for both new cases and relapse tuberculosis as well as one rpoB mutant for under treatment patient. Both molecular tests have agreed to identify one rpoB mutant in the case of failure TB treatment.
Key words: Multidrug-resistant tuberculosis (MDR-TB); GeneXpertMTB/RIF; rpoB
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