Assessing the utility of three TaqMan probes for the diagnosis of tuberculosis and resistance to rifampin and isoniazid in Veracruz, México
Source: Canadian Journal of Microbiology, Volume 58, Number 3, March 2012 , pp. 318-325(8)
Publisher: NRC Research Press
Abstract:Mutations at codons 526 and 531 in the rpoB gene and at 315 in the katG gene are considered diagnostic markers for resistance to rifampin and isoniazid in tuberculosis. The aim of this study was to design and evaluate three TaqMan probes for the identification of these mutations in 138 respiratory samples positive for acid-fast bacilli, and 32 clinical isolates from a region with considerable levels of drug resistance. The specificities of the probes for the diagnosis of resistance to both drugs were 100%; however, the sensitivities were calculated to be 50% for isoniazid and 56% for rifampin. DNA sequencing of rpoB and katG; and the spoligotyping assay of the clinical isolates, confirmed the diversity of the mutations and the presence of 11 spoligotypes with a shared international type and eight unique spoligotypes. Analysis of the respiratory samples identified 22 (16%) as drug-resistant and 4 (3%) as multidrug-resistant tuberculosis. The diagnostic value of the TaqMan probes was compromised by the diversity of mutations found in the clinical isolates. This highlights the need for better understanding of the molecular mechanisms responsible for drug resistance prior to the use of molecular probes, especially in regions with significant levels of drug-resistant tuberculosis.
Document Type: Research Article
Affiliations: 1: Instituto de Salud Pública, Universidad Veracruzana, Av. Luis Castelazo Ayala s/n, A.P. 57, Col. Industrial Animas, Xalapa, Veracruz, 91190 México. 2: Unidad de Investigación Médica de Zacatecas, IMSS, México. 3: Laboratorio Estatal de Salud Pública, Servicios de Salud de Veracruz, México.
Publication date: March 27, 2012
- Published since 1954, this monthly journal contains new research in the field of microbiology including applied microbiology and biotechnology; microbial structure and function; fungi and other eucaryotic protists; infection and immunity; microbial ecology; physiology, metabolism and enzymology; and virology, genetics, and molecular biology. It also publishes review articles and notes on an occasional basis, contributed by recognized scientists worldwide.
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