Rapid identification and susceptibility testing of Mycobacterium tuberculosis from MGIT cultures with luciferase reporter mycobacteriophages

Niaz Banaiee, Miriam Bobadilla-del-Valle, Paul F. Riska, Svetoslav Bardarov, Peter M. Small, Alfredo Ponce-de-Leon, William R. Jacobs, Graham F. Hatfull, Jose Sifuentes-Osornio

Research output: Contribution to journalArticle

40 Scopus citations

Abstract

In a prospective study conducted in a diagnostic laboratory in Mexico City, luciferase reporter mycobacteriophages (LRPs) were evaluated for their utility and performance in identification and antibiotic-susceptibility testing of Mycobacterium tuberculosis complex (MTC) isolates from MGIT-960 cultures. Eighty-four consecutive MGIT cultures recovered from 54 patients were included in this study. The LRPs confirmed mycobacterial growth in 79 (94%) of 84 MGIT cultures. Failure to confirm growth was due to low inoculum (n = 1) or growth with non-tuberculous mycobacteria (n = 4). The median time to confirmation of MGIT cultures was 1 day (range 1-55). Confirmed cultures were identified with p-nitro-α-acetylamino-β-hydroxypropiophenone (NAP), a selective inhibitor of MTC species, and results obtained with LRPs were compared with those obtained by BACTEC-460. The sensitivity and specificity of the LRP NAP test were respectively 97 and 100%, and the median turnaround time for identification was 3 days with both methods. The accuracy and speed of the LRPs for susceptibility testing with rifampicin, streptomycin, isoniazid and ethambutol were compared with BACTEC-460 and discrepant results were tested by the conventional agar proportion method. In total, 72 MTC cultures were tested. The overall agreement between the LRPs and BACTEC-460 was 98.6%. Four isolates (5.6%) were falsely identified as ethambutol-resistant. The median turnaround time for susceptibility testing was 3 days (range 3-57) with the LRPs and 9 days (range 7-29) with BACTEC-460. LRPs offer an accurate and rapid approach for identification and susceptibility testing of M. tuberculosis from MGIT-960 cultures.

Original languageEnglish (US)
Pages (from-to)557-561
Number of pages5
JournalJournal of Medical Microbiology
Volume52
Issue number7
DOIs
StatePublished - Jul 1 2003

ASJC Scopus subject areas

  • Microbiology
  • Microbiology (medical)

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