COBAS® TaqMan® MTB, smear positivity grade and MGIT culture; correlation analyses of three methods for bacillary quantification

Kinuyo Chikamatsu; Akio Aono; Tomoko Kato; Akiko Takaki; Hiroyuki Yamada; Yuka Sasaki; Kiyohiko Izumi; Lina Yi; Satoshi Mitarai

doi:10.1016/j.jiac.2015.09.005

COBAS® TaqMan® MTB, smear positivity grade and MGIT culture; correlation analyses of three methods for bacillary quantification

J Infect Chemother. 2016 Jan;22(1):19-23. doi: 10.1016/j.jiac.2015.09.005. Epub 2015 Oct 31.

Authors

Kinuyo Chikamatsu¹, Akio Aono², Tomoko Kato², Akiko Takaki², Hiroyuki Yamada², Yuka Sasaki³, Kiyohiko Izumi⁴, Lina Yi⁵, Satoshi Mitarai⁶

Affiliations

¹ Department of Mycobacterium Reference and Research, The Research Institute of Tuberculosis, Japan Anti-Tuberculosis Association, Kiyose, Japan. Electronic address: [email protected].
² Department of Mycobacterium Reference and Research, The Research Institute of Tuberculosis, Japan Anti-Tuberculosis Association, Kiyose, Japan.
³ Department of Respiratory Medicine, Fukujuji Hospital, Japan Anti-Tuberculosis Association, Kiyose, Japan.
⁴ 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.
⁵ 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.
⁶ 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.

PMID: 26527538
DOI: 10.1016/j.jiac.2015.09.005

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.

Keywords: COBAS TaqMan MTB; Cycle threshold value; Mycobacterium tuberculosis; Quantification; Smear positivity grade.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Bacteriological Techniques / methods*
Evaluation Studies as Topic
Humans
Mycobacterium tuberculosis / growth & development*
Mycobacterium tuberculosis / isolation & purification
Real-Time Polymerase Chain Reaction
Sensitivity and Specificity
Sputum
Statistics as Topic
Tuberculosis, Pulmonary / diagnosis*