Molecular detection of rifampicin resistance in multidrug-resistant Mycobacterium tuberculosis strains from North-Eastern Romania

Introduction: Multidrug-resistant tuberculosis (MDR-TB) represents an important public health problem. Rapid molecular methods detect the mutations responsible for drug- resistance and can shorten the time required for diagnosis and initiation of appropriate therapy. The objectives of our study were to optimize a multiplex allele-specific PCR technique (MAS-PCR) to detect rpoB mutations and to specify the type and frequency of these mutations. Material and methods: We have tested 47 non-duplicate MDR-TB, including extensively drugresistant tuberculosis (XDR-TB) strains, identified during 2007-2012, using MAS-PCR for detection of mutations in rpoB codons 531, 526 and 516. Results: The most common mutation was located in codon 531 (63.82%), while only 12.76% and 10.63% of the strains showed mutations in codon 516 and 526, respectively; for six strains we have not identified mutation in the targeted codons. Conclusion: MAS-PCR revealed the mutations prevalent in our region, with good sensitivity (87.2%), suggesting the usefulness of this test in the rapid diagnosis of MDR-TB