Drug resistance in Mycobacterium tuberculosis clinical isolates from Brazil: Phenotypic and genotypic methods - 11/09/11

Doi : 10.1016/j.biopha.2011.04.021

Marcelo Miyata ^a,^⁎ , Fernando Rogério Pavan ^a, Daisy Nakamura Sato ^b, Leonardo Biancolino Marino ^a, Mario Hiroyuki Hirata ^c, Rosilene Fressati Cardoso ^d, Fernando Augusto Fiúza de Melo ^e, Cleslei Fernando Zanelli ^a, Clarice Queico Fujimura Leite ^a
^a School of Pharmaceutical Sciences, Biological Sciences Department, Paulista State University, Rodovia Araraquara-Jaú km 1, 14800-901 Araraquara, SP, Brazil
^b Adolfo Lutz Institute, Ribeirão Preto Unit, Ribeirão Preto, SP, Brazil
^c School of Pharmaceutical Sciences, University of São Paulo, São Paulo, SP, Brazil
^d Department of Clinical Analyses and Biomedicine, State University of Maringá, Maringá, PR, Brazil
^e Clemente Ferreira Institute, São Paulo, SP, Brazil

Corresponding author.

Bienvenue sur EM-consulte, la référence des professionnels de santé.
L’accès au texte intégral de cet article nécessite un abonnement.

pages	4
Iconographies	2
Vidéos	0
Autres	0

Abstract

We determined the susceptibility profile of 80 Mycobacterium tuberculosis (MTB) clinical isolates from Brazil against isoniazid (INH) and rifampicin (RIF) drugs by two phenotypic methods (Resazurin Microtiter Assay - REMA and BACTEC™ MGIT™ Mycobacterial Detection System). DNA polymorphisms were also determined by PCR-SSCP in isolates resistant to INH and RIF. BACTEC™ MGIT™ 960 detected 22 susceptible isolates to INH and RIF, 48 MDR isolates (resistant at least to INH and RIF) and nine mono-resistant isolates (eight to INH and one to RIF). REMA performance was determined by Receiver Operating Characteristic curve, whose assay was validated utilizing as reference the BACTEC™ MGIT™ 960 system. ROC curve showed cut-off values of 0.0625μg/mL and 0.125μg/mL, for INH and RIF, respectively. REMA-INH demonstrated sensitivity and specificity of 100% while REMA-RIF showed sensitivity of 97.2% and specificity of 100%. PCR-SSCP detected DNA polymorphisms in 87.5% and 75.5% of isolates classified as INH-resistant and RIF-resistant, respectively. One discordant sample found to RIF (resistant by BACTEC™ MGIT™ 960 and susceptible by REMA) showed no mutation by PCR-SSCP. In conclusion, our studies demonstrated that the combination of phenotypic method REMA, which allowed rapid detection of MDR-MTB with higher levels of sensitivity and specificity, with the genotypic method PCR-SSCP, which demonstrated high accuracy in the search of polymorphisms in the resistance genes, proved to be a useful strategy to study MDR-MTB clinical isolates from national reference center located in São Paulo city.

Le texte complet de cet article est disponible en PDF.

Keywords : Mycobacterium tuberculosis, REMA, PCR-SSCP