title: COBAS® TaqMan® MTB, smear positivity grade and MGIT culture; correlation analyses of three methods for bacillary quantification.
abstract: We investigated the correlation between the cycle threshold (Ct) value of the COBAS(®) TaqMan(®) MTB (TaqMan MTB), the mycobacterial smear positivity grade, and the time to detection (TTD) in the Mycobacteria Growth Indicator Tube (MGIT) for quantification of Mycobacterium tuberculosis (MTB). For 57 sputum samples, significant correlations were observed between the Ct value, the smear positivity grade, and the MGIT TTD (Spearman's rank correlation coefficient: r(s) = -0.940, P < 0.001 and Pearson's correlation coefficient: r(p) = 0.737, P < 0.001). In addition, a correlation was observed between the number of bacteria estimated based on the smear positivity grade and the number of MTB bacilli calculated by the Ct value (r(s) = 0.930, P < 0.001). This study has demonstrated the possible estimation of the smear positivity grade and MGIT TTD using the Ct value of TaqMan MTB, which is based on a real-time PCR system, for diagnostic samples.
authors.affiliation: Department of Mycobacterium Reference and Research, The Research Institute of Tuberculosis, Japan Anti-Tuberculosis Association, Kiyose, Japan. Electronic address: chikamatsu@jata.or.jp.
authors.forename: Kinuyo
authors.initials: K
authors.lastname: Chikamatsu
authors.affiliation: Department of Mycobacterium Reference and Research, The Research Institute of Tuberculosis, Japan Anti-Tuberculosis Association, Kiyose, Japan.
authors.forename: Akio
authors.initials: A
authors.lastname: Aono
authors.affiliation: Department of Mycobacterium Reference and Research, The Research Institute of Tuberculosis, Japan Anti-Tuberculosis Association, Kiyose, Japan.
authors.forename: Tomoko
authors.initials: T
authors.lastname: Kato
authors.affiliation: Department of Mycobacterium Reference and Research, The Research Institute of Tuberculosis, Japan Anti-Tuberculosis Association, Kiyose, Japan.
authors.forename: Akiko
authors.initials: A
authors.lastname: Takaki
authors.affiliation: Department of Mycobacterium Reference and Research, The Research Institute of Tuberculosis, Japan Anti-Tuberculosis Association, Kiyose, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Yamada
authors.affiliation: Department of Respiratory Medicine, Fukujuji Hospital, Japan Anti-Tuberculosis Association, Kiyose, Japan.
authors.forename: Yuka
authors.initials: Y
authors.lastname: Sasaki
authors.affiliation: Department of Epidemiology and Clinical Research, The Research Institute of Tuberculosis, Japan Anti-Tuberculosis Association, Kiyose, Japan; Department of Basic Mycobacteriology, Graduate School of Biomedical Science, Nagasaki University, Nagasaki, Japan.
authors.forename: Kiyohiko
authors.initials: K
authors.lastname: Izumi
authors.affiliation: Department of Respiratory Medicine, Fukujuji Hospital, Japan Anti-Tuberculosis Association, Kiyose, Japan; Department of Basic Mycobacteriology, Graduate School of Biomedical Science, Nagasaki University, Nagasaki, Japan.
authors.forename: Lina
authors.initials: L
authors.lastname: Yi
authors.affiliation: Department of Mycobacterium Reference and Research, The Research Institute of Tuberculosis, Japan Anti-Tuberculosis Association, Kiyose, Japan; Department of Basic Mycobacteriology, Graduate School of Biomedical Science, Nagasaki University, Nagasaki, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Mitarai
mesh_terms: D001431:Bacteriological Techniques / Q000379:methods*; D005069:Evaluation Studies as Topic; D006801:Humans; D009169:Mycobacterium tuberculosis / Q000254:growth & development* / Q000302:isolation & purification; D060888:Real-Time Polymerase Chain Reaction; D012680:Sensitivity and Specificity; D013183:Sputum; D013223:Statistics as Topic; D014397:Tuberculosis, Pulmonary / Q000175:diagnosis*
keywords: COBAS TaqMan MTB; Cycle threshold value; Mycobacterium tuberculosis; Quantification; Smear positivity grade