title: Modified protocol for drug susceptibility testing of MGIT cultures of Mycobacterium tuberculosis by the MGIT 960.
abstract: A rapid detection of resistance in Mycobacterium tuberculosis is crucial for management and control of tuberculosis. This study evaluated a more rapid and cost-effective drug susceptibility testing (DST) protocol using primary isolates of M. tuberculosis in mycobacteria growth indicator tube (MGIT). Ninety-four M. tuberculosis isolates in MGIT were subjected to DST by the manufacturer's method, i.e., primary isolates were subcultured and DST was performed from positive cultures for a maximum of 5days; and by our modified method, i.e., DST was performed directly from primary MGIT cultures positive for more than 5days. Results were concordant for 76 (81%) isolates. Agreement between both methods was 92.0%, 98.9%, 97.7%, and 95.5% for streptomycin, isoniazid, rifampicin, and ethambutol, respectively. Six isolates failed to grow on the recommended method, including 3 resistant isolates. Not performing subculture of primary M. tuberculosis isolates yields reliable results, decreasing the turnaround time and the cost of the test.
authors.affiliation: Núcleo de Tuberculose e Micobacterioses, Centro de Bacteriologia, Instituto Adolfo Lutz, São Paulo, SP, Brazil.
authors.forename: Aline Gois
authors.initials: AG
authors.lastname: Adami
authors.affiliation: Núcleo de Tuberculose e Micobacterioses, Centro de Bacteriologia, Instituto Adolfo Lutz, São Paulo, SP, Brazil.
authors.forename: Juliana Failde
authors.initials: JF
authors.lastname: Gallo
authors.affiliation: Núcleo de Tuberculose e Micobacterioses, Centro de Bacteriologia, Instituto Adolfo Lutz, São Paulo, SP, Brazil. Electronic address: jupinhata@ial.sp.gov.br.
authors.forename: Juliana Maira Watanabe
authors.initials: JM
authors.lastname: Pinhata
authors.affiliation: Núcleo de Tuberculose e Micobacterioses, Centro de Bacteriologia, Instituto Adolfo Lutz, São Paulo, SP, Brazil.
authors.forename: Maria Conceição
authors.initials: MC
authors.lastname: Martins
authors.affiliation: Núcleo de Tuberculose e Micobacterioses, Centro de Bacteriologia, Instituto Adolfo Lutz, São Paulo, SP, Brazil.
authors.forename: Carmen Maria Saraiva
authors.initials: CM
authors.lastname: Giampaglia
authors.affiliation: Núcleo de Tuberculose e Micobacterioses, Centro de Bacteriologia, Instituto Adolfo Lutz, São Paulo, SP, Brazil.
authors.forename: Rosangela Siqueira
authors.initials: RS
authors.lastname: de Oliveira
mesh_terms: D000995:Antitubercular Agents / Q000494:pharmacology*; D008826:Microbial Sensitivity Tests / Q000379:methods*; D009169:Mycobacterium tuberculosis / Q000187:drug effects* / Q000302:isolation & purification; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity; D013997:Time Factors; D014376:Tuberculosis / Q000175:diagnosis / Q000382:microbiology
chemical_list: D000995:Antitubercular Agents
keywords: Diagnostics; Drug resistance; MGIT 960; Mycobacterium tuberculosis; Tuberculosis