Multidrug Resistant Mycobacterium tuberculosis: A Retrospective katG and rpoB Mutation Profile Analysis in Isolates from a Reference Center in Brazil

Abstract

BackgroundMultidrug resistance is a critical factor in tuberculosis control. To gain better understanding of multidrug resistant tuberculosis in Brazil, a retrospective study was performed to compare genotypic diversity and drug resistance associated mutations in Mycobacterium tuberculosis isolates from a national reference center.Methods and FindingsNinety-nine multidrug resistant isolates from 12 Brazilian states were studied. Drug-resistance patterns were determined and the rpoB and katG genes were screened for mutations. Genotypic diversity was investigated by IS6110-RFLP and Luminex 47 spoligotyping. Mutations in rpoB and katG were seen in 91% and 93% of the isolates, respectively. Codon 315 katG mutations occurred in 82.8% of the isolates with a predominance of the Ser315Thr substitution. Twenty-five isolates were clustered in 11 groups with identical IS6110-RFLP patterns while 74 showed unique patterns with no association between mutation frequencies or susceptibility profiles. The most prevalent spoligotyping lineages were LAM (47%), T (17%) and Haarlen (12%). The Haarlen lineage showed a higher frequency of codon 516 rpoB mutations while codon 531 mutations prevailed in the other isolates.ConclusionsOur data suggest that there were no major multidrug resistant M. tuberculosis strains transmitted among patients referred to the reference center, indicating an independent acquisition of resistance. In addition, drug resistance associated mutation profiles were well established among the main spoligotyping lineages found in these Brazilian multidrug resistant isolates, providing useful data for patient management and treatment.

Locked Nucleic Acid Probe-Based Real-Time PCR Assay for the Rapid Detection of Rifampin-Resistant Mycobacterium tuberculosis

“…Reported mutations associated with RFP-resistance in the gene were accumulated in the 81-bp (codon 507 to codon 533) region called the rifampin resistance determination region (RRDR) [ 8 – 10 ]. Moreover, the most high-frequency mutations were localized at codon 516, 526, and 531, as observed worldwide [ 9 , 11 , 12 ]. Consequently, the rpoB genotype of M .…”

Development and in-use evaluation of a novel Luminex MicroPlex microsphere-based (TRIOL) assay for simultaneous identification of Mycobacterium tuberculosis and detection of first-line and second-line anti-tuberculous drug resistance in China

“…Inclusion of specific primers for the identification of non-tuberculous mycobacteria and spoligotyping may further enhance the use of the TRIOL assay for future epidemiological studies 28 29 31. As for the detection of resistance mutations to anti-tuberculous drugs, the overall and drug-specific specificities were excellent (100%).…”

Rapid Detection of Mycobacterium tuberculosis Strains Resistant to Isoniazid and/or Rifampicin: Standardization of Multiplex Polymerase Chain Reaction Analysis

“…[3][4][5][6] Rifampicin (R), resistance is mostly (96%) due to mutations in an 81-(base pair) bp "hot-spot" region of the rpoB gene that encodes the β-subunit of RNA polymerase, especially in codons 531 (43-56%) and 526 (8-31%). [7][8][9][10] Several molecular methods are available for detection of drug resistance mutations, including denaturing gradient gel electrophoresis, conformation-sensitive gel electrophoresis, temperature gradient capillary electrophoresis, denaturing highperformance liquid chromatography, high-density oligonucleotide arrays, and high-resolution melting analysis. [11][12][13][14][15][16][17] These methods vary in sensitivity and are either labor intensive, require sophisticated equipment to perform analyses, or present ambiguity in interpretation.…”