Phenotypic and genotypic characterization of drug-resistant Mycobacterium tuberculosis strains.
Of 142 pulmonary tuberculosis patients, 76 were considered high risk for the development of resistance, and 24 were confirmed as resistant strain carriers. Resistant isoniazid strains presented a high frequency of katG and ahpC mutations (90%) correlated with an MIC >4 microg/mL (94%). inhA mutations were not seen. rpoB mutations were identified in 78.6% of rifampicin-resistant strains, usually in codon 531 (72.7%), and 75% had an MIC >16 microg/mL. katG and rpoB mutations recognized 88.2% of multidrug-resistant strains and proved more efficient than the katG and rpoB mutations alone. Seventy percent of resistant pyrazinamide strains had pncA mutations between genes 136 and 188, 62.5% of them with an MIC >900 microg/mL. Pyrazinamidase inactivity was not an efficient resistance marker because 60% of pncA-mutated strains maintained enzymatic activity despite displaying good correlation with high resistance levels. Resistant ethambutol strains had embB mutations in codon 306, with MIC >16 microg/mL.
Clemente
Wanessa Trindade
WT
Departamento de Propedêutica Complementar da Faculdade de Medicina da Universidade Federal de Minas Gerais. Av. Alfredo Balena, 190, Santa Efigênia, Belo Horizonte, MG, CEP 30130-100, Brazil. wanclemente@yahoo.com.br
Soares Lima
Stella Sala
SS
Palaci
Moises
M
Silva
Márcia S N
MS
Sumnienski Rodrigues
Vivian F
VF
Dalla Costa
Elis R
ER
Possuelo
Lia
L
Cafrune
Patrícia Izquierdo
PI
Ribeiro
Fabíola Karla
FK
Gomes
Harisson M
HM
Serufo
José Carlos
JC
D000995:Antitubercular Agents / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D001938:Brazil / Q000453:epidemiology; D024881:Drug Resistance, Bacterial / Q000235:genetics*; D005838:Genotype; D006801:Humans; D008826:Microbial Sensitivity Tests; D009154:Mutation; D009169:Mycobacterium tuberculosis / Q000145:classification / Q000187:drug effects* / Q000235:genetics; D010641:Phenotype; D012150:Polymorphism, Restriction Fragment Length; D017422:Sequence Analysis, DNA; D018088:Tuberculosis, Multidrug-Resistant / Q000453:epidemiology* / Q000382:microbiology; D014397:Tuberculosis, Pulmonary / Q000453:epidemiology* / Q000382:microbiology
D000995:Antitubercular Agents; D001426:Bacterial Proteins