Drug resistance in Mycobacterium tuberculosis clinical isolates from Brazil: phenotypic and genotypic methods.
Biomed Pharmacother
; 65(6): 456-9, 2011 Sep.
Article
em En
| MEDLINE
| ID: mdl-21880463
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.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Testes de Sensibilidade Microbiana
/
Tuberculose Resistente a Múltiplos Medicamentos
/
Genes MDR
/
Mycobacterium tuberculosis
Tipo de estudo:
Diagnostic_studies
/
Prognostic_studies
Limite:
Humans
País/Região como assunto:
America do sul
/
Brasil
Idioma:
En
Revista:
Biomed Pharmacother
Ano de publicação:
2011
Tipo de documento:
Article
País de afiliação:
Brasil