Rapid Susceptibility Testing of MDR M. tuberculosis

DESCRIPTION (provided by applicant): This Phase I research will test the feasibility of using mycolic acid analysis as a very rapid test for drug susceptibility of Mycobacterium tuberculosis. The significance of TB is evident in that more than one-third of the world's population is infected by M. tuberculosis and multi-drug resistant TB is both a current serious health risk and potential bioterrorism weapon. Tuberculosis causes more death and suffering than any other infectious agent and is especially prevalent in HIV-infected populations. The current testing method for susceptibility of TB to treatment drugs averages nearly a week to obtain results and may be compromised by false results caused by bacterial contaminants. High performance liquid chromatography (HPLC) of mycolic acids enables rapid, inexpensive identification of mycobacteria as profiles are characteristic of the various species. When exposed to treatment drugs such as isoniazid, susceptible TB strains diminish in mycolic acid content within 20 minutes, as compared to the untreated controls, and resistant strains do not show this loss but gain in mycolic acid amount with time. Susceptible and resistant strains will be inoculated into control and inhibitor-containing vials of a commercial test system. The assay will be performed by PLC analysis of mycolic acid content over timed intervals (up to 72 h.). Comparative quantities of mycolic acids indicate growth/no growth and the characteristic pattern of mycolics assure that contaminants are not responsible for the result. As an alternative approach, intermediates/precursors such as hexacosanoic acid (C26:0) will be assayed using a similar research protocol and quantitation by HPLC analysis. PROPOSED COMMERCIAL APPLICATION: The major product will be the software and hardware necessary to perform the HPLC testing method. Internal standards and the HPLC Calibration mixture for the assay will also be commercial products. Phase II of the project will entail validating the methodology for multiple strains and additional antibiotics. Optimization for performing analyses directly from signal positive bottles and application to direct from sputum will be explored.