title: Phenotypic and genotypic characterization of drug-resistant Mycobacterium tuberculosis strains.
abstract: 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.
authors.affiliation: 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
authors.forename: Wanessa Trindade
authors.initials: WT
authors.lastname: Clemente
authors.forename: Stella Sala
authors.initials: SS
authors.lastname: Soares Lima
authors.forename: Moises
authors.initials: M
authors.lastname: Palaci
authors.forename: Márcia S N
authors.initials: MS
authors.lastname: Silva
authors.forename: Vivian F
authors.initials: VF
authors.lastname: Sumnienski Rodrigues
authors.forename: Elis R
authors.initials: ER
authors.lastname: Dalla Costa
authors.forename: Lia
authors.initials: L
authors.lastname: Possuelo
authors.forename: Patrícia Izquierdo
authors.initials: PI
authors.lastname: Cafrune
authors.forename: Fabíola Karla
authors.initials: FK
authors.lastname: Ribeiro
authors.forename: Harisson M
authors.initials: HM
authors.lastname: Gomes
authors.forename: José Carlos
authors.initials: JC
authors.lastname: Serufo
mesh_terms: 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
chemical_list: D000995:Antitubercular Agents; D001426:Bacterial Proteins