Distribution of rpoB mutations among multidrug-resistant Mycobacterium tuberculosis (MDRTB) strains from Thailand and development of a rapid method for mutation detection

Abstract

Since rifampicin resistance is a surrogate marker for multidrug-resistant Mycobacterium tuberculosis (MDRTB), the present study aimed to investigate rpoB mutations conferring rifampicin resistance in M. tuberculosis strains from Thailand, and to develop a rapid, inexpensive and simple PCR-based method for rapid detection of MDRTB. Overall, 267 M. tuberculosis isolates, including 143 MDRTB isolates, were investigated. Isolates of the Beijing strain predominated among the MDRTB isolates (79.1%), but accounted for only 45.5% of the susceptible isolates. Mutations in the rpoB gene were found most commonly at codons 531, 526 and 516 (58%, 25.2% and 9.1%, respectively). A multiplex allele-specific PCR was developed and tested with 216 clinical isolates. In comparison with the proportion method, the method showed 94.2% sensitivity and 100% specificity, and had a 100% positive predictive value and a 95% negative predictive value, which suggested that this method could be useful for screening for MDRTB, particularly in resource-limited countries.

Molecular Characterization of Multidrug- and Extensively Drug-Resistant Mycobacterium tuberculosis Strains in Jiangxi, China

“…Second, mutations within the RRDR of rpoB have been reported to occur in 95% or higher of the RIF-resistant isolates (9,36,54). Third, RIF resistance is an excellent surrogate marker for MDR M. tuberculosis (26,37). In the present study, six novel rpoB mutations were identified, and they all fell outside of the RRDR region of the rpoB gene.…”

Detection of Mycobacterium tuberculosis and Drug Resistance: Opportunies and Challenges in Morocco

“…Rare loci found outside the hotspot region of rpoB are associated with resistance without associated mutation known for conferring resistance (Taniguchi, 1996;Fang, 1999;Schilke, 1999;Yuen, 1999;Heep, 2001;Zhang, 2005;Rigouts, 2007;Prammananan, 2008).…”

“…Mutated strains in Val146Phe (Heep, 2001;Rigouts, 2007;Prammananan, 2008) show a lowlevel resistance (MIC 4 µg/ml) (Rigouts, 2007). The Ala381Val mutation (Taniguchi, 1996) is described on a strain of MIC 200, with no other mutation on the rpoB gene.…”

Rapid Detection of Mycobacterium tuberculosis and Rifampin Resistance by Use of On-Demand, Near-Patient Technology

“…The assay proved to be simple, rapid, specific, and highly sensitive in tests on isolates of M. tuberculosis from New York City, Madrid (42), India, and Mexico (51). As most rifampin-resistant isolates are also resistant to isoniazid, rifampin resistance can be used as a marker for MDR M. tuberculosis (36,44,49). However, like all nucleic acid amplification-based assays for M. tuberculosis detection (15), this assay was too complex and too prone to operator errors, sample cross-contamination, and biohazards for rapid near-patient use.…”