title: Autoluminescent Mycobacterium tuberculosis for rapid, real-time, non-invasive assessment of drug and vaccine efficacy.
abstract: Preclinical efforts to discover and develop new drugs and vaccines for tuberculosis are hampered by the reliance on colony-forming unit (CFU) counts as primary outcomes for in vivo efficacy studies and the slow growth of Mycobacterium tuberculosis. The utility of bioluminescent M. tuberculosis reporter strains for real-time in vitro and ex vivo assessment of drug and vaccine activity has been demonstrated but a simple, non-invasive, real-time surrogate marker to replace CFU counts for real-time evaluation of drug and vaccine efficacy in vivo has not been described. We describe the development of a fully virulent and stable autoluminescent strain of M. tuberculosis and proof-of-concept experiments demonstrating its utility for in vivo bioluminescence imaging to assess the efficacy of new drugs and vaccines for tuberculosis in a mouse model. Relative light unit (RLU) counts paralleled CFU counts during the active phase of bacterial growth, with a lower limit of detection of approximately 10(6) CFU in live, anesthetized mice. Experiments distinguishing active from inactive anti-tuberculosis drugs and bacteriostatic drug effects from bactericidal effects were completed in less than 5 days. The ability of a recombinant BCG vaccine to limit bacterial growth was demonstrated within 3 weeks. Use of this autoluminescent reporter strain has the potential to drastically reduce the time, effort, animals and costs consumed in the evaluation of drug activity in vitro and the in vivo assessment of drug and vaccine efficacy.
authors.affiliation: Center for Tuberculosis Research, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America.
authors.forename: Tianyu
authors.initials: T
authors.lastname: Zhang
authors.forename: Si-Yang
authors.initials: SY
authors.lastname: Li
authors.forename: Eric L
authors.initials: EL
authors.lastname: Nuermberger
mesh_terms: D000818:Animals; D000995:Antitubercular Agents / Q000494:pharmacology* / Q000627:therapeutic use; D015169:Colony Count, Microbial; D005260:Female; D008163:Luminescent Measurements / Q000379:methods*; D051379:Mice; D008807:Mice, Inbred BALB C; D008826:Microbial Sensitivity Tests; D009169:Mycobacterium tuberculosis / Q000187:drug effects* / Q000254:growth & development / Q000276:immunology* / Q000472:pathogenicity; D013997:Time Factors; D016896:Treatment Outcome; D014376:Tuberculosis / Q000188:drug therapy / Q000276:immunology; D032581:Tuberculosis Vaccines / Q000276:immunology*; D014774:Virulence / Q000187:drug effects
chemical_list: D000995:Antitubercular Agents; D032581:Tuberculosis Vaccines