title: Rapid in vivo detection of isoniazid-sensitive Mycobacterium tuberculosis by breath test.
abstract: There is urgent need for rapid, point-of-care diagnostic tools for tuberculosis (TB) and drug sensitivity. Current methods based on in vitro growth take weeks, while DNA amplification can neither differentiate live from dead organisms nor determine phenotypic drug resistance. Here we show the development and evaluation of a rapid breath test for isoniazid (INH)-sensitive TB based on detection of labelled N2 gas formed specifically from labelled INH by mycobacterial KatG enzyme. In vitro data show that the assay is specific, dependent on mycobacterial abundance and discriminates between INH-sensitive and INH-resistant (S315T mutant KatG) TB. In vivo, the assay is rapid with maximal detection of (15)N2 in exhaled breath of infected rabbits within 5-10 min. No increase in (15)N2 is detected in uninfected animals, and the increases in (15)N2 are dependent on infection dose. This test may allow rapid detection of INH-sensitive TB.
authors.affiliation: Dept. Pharmaceutical Sciences, College of Pharmacy, University of New Mexico, Albuquerque NM 87131 USA.
authors.forename: Seong Won
authors.initials: SW
authors.lastname: Choi
authors.affiliation: Center for Tuberculosis Research, Department of Medicine, Johns Hopkins University, Baltimore MD 21231 USA.
authors.forename: Mamoudou
authors.initials: M
authors.lastname: Maiga
authors.affiliation: Center for Tuberculosis Research, Department of Medicine, Johns Hopkins University, Baltimore MD 21231 USA.
authors.forename: Mariama C
authors.initials: MC
authors.lastname: Maiga
authors.affiliation: Dept. Earth and Planetary Sciences, College of Pharmacy, University of New Mexico, Albuquerque NM 87131 USA.
authors.forename: Viorel
authors.initials: V
authors.lastname: Atudorei
authors.affiliation: Dept. Earth and Planetary Sciences, College of Pharmacy, University of New Mexico, Albuquerque NM 87131 USA.
authors.forename: Zachary D
authors.initials: ZD
authors.lastname: Sharp
authors.affiliation: Center for Tuberculosis Research, Department of Medicine, Johns Hopkins University, Baltimore MD 21231 USA.
authors.forename: William R
authors.initials: WR
authors.lastname: Bishai
authors.affiliation: Dept. Pharmaceutical Sciences, College of Pharmacy, University of New Mexico, Albuquerque NM 87131 USA.
authors.forename: Graham S
authors.initials: GS
authors.lastname: Timmins
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D001944:Breath Tests / Q000379:methods*; D002374:Catalase / Q000235:genetics / Q000378:metabolism; D007538:Isoniazid / Q000737:chemistry / Q000378:metabolism*; D015394:Molecular Structure; D009169:Mycobacterium tuberculosis / Q000302:isolation & purification* / Q000378:metabolism; D009587:Nitrogen Isotopes / Q000032:analysis; D019095:Point-of-Care Systems; D011817:Rabbits; D012680:Sensitivity and Specificity; D014376:Tuberculosis / Q000175:diagnosis*
chemical_list: D001426:Bacterial Proteins; D009587:Nitrogen Isotopes; D002374:Catalase; C480353:katG protein, Mycobacterium tuberculosis; D007538:Isoniazid