title: Time to detection of Mycobacterium tuberculosis as an alternative to quantitative cultures.
abstract: Testing new drugs is critical to improving the treatment of tuberculosis. Quantitative cultures of Mycobacterium tuberculosis on solid media have been used in Phase 1 and 2 trials, but are time and resource intensive. Time to detection (TTD) of growth of M. tuberculosis in automated liquid culture systems is an alternative. TTD has been shown to correlate with CFU in quantitative cultures, and is faster and simpler to perform. We compared TTD in the BACTEC 460 liquid culture system with CFU in a clinical trial that included 110 subjects. Comparing all sputum cultures collected between baseline and 2 months we found a strong negative correlation between log(10) CFU and TTD (rho = -0.91). In addition, when TTD at baseline was compared with 1 and 2 month sputum culture positivity, subjects whose cultures were negative after 1 and 2 months had a significantly longer median baseline TTD compared with subjects whose cultures were positive at 1 and 2 months (5 vs. 3 days and 3 vs. 2 days, respectively). TTD compares closely with CFU and represents a faster, simpler alternative to quantitative cultures.
authors.affiliation: Tuberculosis Research Unit, Department of Medicine, Case Western Reserve University and University Hospitals Case Medical Center, Cleveland, OH 44106-5083, USA. cmb148@case.edu
authors.forename: C M
authors.initials: CM
authors.lastname: Bark
authors.forename: A
authors.initials: A
authors.lastname: Okwera
authors.forename: M L
authors.initials: ML
authors.lastname: Joloba
authors.forename: B A
authors.initials: BA
authors.lastname: Thiel
authors.forename: J G
authors.initials: JG
authors.lastname: Nakibali
authors.forename: S M
authors.initials: SM
authors.lastname: Debanne
authors.forename: W H
authors.initials: WH
authors.lastname: Boom
authors.forename: K D
authors.initials: KD
authors.lastname: Eisenach
authors.forename: J L
authors.initials: JL
authors.lastname: Johnson
mesh_terms: D000293:Adolescent; D000328:Adult; D017322:Clinical Trials, Phase II as Topic; D015169:Colony Count, Microbial; D003470:Culture Media / Q000494:pharmacology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009169:Mycobacterium tuberculosis / Q000302:isolation & purification*; D012189:Retrospective Studies; D013183:Sputum / Q000382:microbiology*; D013997:Time Factors; D014397:Tuberculosis, Pulmonary / Q000453:epidemiology / Q000382:microbiology*; D014454:Uganda / Q000453:epidemiology; D055815:Young Adult
chemical_list: D003470:Culture Media