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The Direct Repeat locus of the Mycobacterium tuberculosis complex (MTC) is a member of the CRISPR (Clustered regularly interspaced short palindromic repeats) sequences family. Spoligotyping is the widely used PCR-based reverse-hybridization blotting technique that assays the genetic diversity of this locus and is useful both for clinical laboratory,(More)
In conclusion, it is important to realize that there is no "stand alone" assay for the identification of NTM. Many new species may not be recognized in all assays. Newer molecular tests are more accurate for identification than phenotypic tests and have significantly improved turnaround time. Clinical significance of an isolate should be determined,(More)
Isoniazid (INH) and rifampin (RIF) are two of the most important antituberculosis drugs, and resistance to both of these drugs can often result in treatment failure and fatal clinical outcome. Resistance to these two first-line drugs is most often attributed to mutations in the katG, inhA, and rpoB genes. Historically, the identification and testing of the(More)
Salicylate induces multiple antibiotic resistance in various bacterial species. Here we investigated the effect of salicylate on the susceptibility of Mycobacterium tuberculosis to a range of antituberculosis (anti-TB) drugs. In the presence of salicylate, the killing effects of isoniazid (INH), rifampin (RMP), ethambutol (EMB), streptomycin (STR), and(More)
Multidrug-resistant (MDR) strains of Mycobacterium tuberculosis have emerged worldwide. In many countries and regions, these resistant strains constitute a serious threat to the efficacy of tuberculosis control programs. An important element in gaining control of this epidemic is developing an understanding of the molecular basis of resistance to the most(More)
An urgent question that needs to be addressed rapidly by the mycobacteriology laboratory is whether Mycobacterium tuberculosis complex or NTM is involved. NAA assays are excellent tools for the purpose, and can be used directly on the clinical specimens of patients suspected of having mycobacterial disease, allowing same-day reporting of results. The CDC(More)
Testing for susceptibility to pyrazinamide (PZA) and analysis of the pncA gene sequences of 423 Mycobacterium tuberculosis complex isolates have revealed a unique silent nucleotide substitution that enables the rapid identification of "M. canettii" (proposed name). Moreover, the lack of a defined mutation within the pncA gene strongly suggests that an(More)
Xpert-MTB/Rif is one of the most frequently used molecular screening tests for multidrug-resistant tuberculosis worldwide. We report false-negative assay results in the presence of rpoB Leu533Pro, which is associated with low-level phenotypic rifampin resistance. Accurate and timely confirmation of rifampin susceptibility results obtained with Xpert-MTB/Rif(More)
BACKGROUND Pyrazinamide is a paradoxical frontline tuberculosis drug characterized by high in vivo sterilizing activity but poor in vitro activity. This separation in pyrazinamide activity reflects differences between the in vivo tissue environment and in vitro culture conditions. The well-known acid pH requirement for pyrazinamide activity was discovered(More)
A prospective study was organized by using a total of 1,585 consecutive clinical specimens to determine whether biomass obtained from positive growth in the MGIT 960 system could be used directly in AccuProbe DNA hybridization tests, the PCR-based Inno-LiPA Rif.TB (LiPA) assay, and a PCR-based DNA sequencing of the rpoB gene for the rapid identification of(More)