Rapid film-based determination of antibiotic susceptibilities of Mycobacterium tuberculosis strains by using a luciferase reporter phage and the Bronx box

Detecting antibiotic resistance in Mycobacterium tuberculosis is becoming i ncreasingly important with the global recognition of drug-resistant strains and their adverse impact on clinical outcomes. Current methods of suscepti bility testing are either time-consuming or costly; rapid, reliable, simple , and inexpensive methods would be highly desirable, especially in the deve loping world where most tuberculosis is found. The luciferase reporter phag e is a unique reagent well-suited for this purpose: upon infection with via ble mycobacteria, it produces quantifiable light which is not observed in m ycobacterial cells treated with active antimicrobials. In this report, we d escribe a modification of our original assay, which allows detection of the emitted light with a Polaroid film box designated the Bronx Box. The techn ique has been applied to 25 M. tuberculosis reference and clinical strains, and criteria are presented which allow rapid and simple discrimination amo ng strains susceptible or resistant to isoniazid and rifampin, the major an tituberculosis agents.