Isothermal target and probe amplification for Mycobacterium tuberculosis identification from broth cultures.
METHODS
Various methods are used to identify Mycobacterium tuberculosis complex (MTC) from broth cultures. The isothermal target and probe amplification (iTPA) method has recently been introduced as a simple and cost-effective molecular assay.


OBJECTIVE
To evaluate the diagnostic  performance of the iTPA method.


METHODS
A total of 175 specimens from the Mycobacteria Growth Indicator Tube (MGIT) 960 broth culture system were evaluated. The immunochromatographic test (ICT) and real-time quantitative PCR (RQ-PCR) were compared with the iTPA method.


RESULTS
MTC was  identified in 71/131 MGIT-positive specimens, including 60 ICT-positive and 11 ICT- negative/PCR-positive specimens. The sensitivity and specificity of the ICT assay were respectively 84.5% (95%CI 74.0-92.0) and 100% (95%CI 94.0-100). These 71 specimens were all MTC-positive with  the iTPA method also. Sixty non-tuberculous mycobacteria specimens and 44 MGIT-negative specimens were all MTC-negative with the iTPA method.


CONCLUSIONS
Our data show that the diagnostic performance of the iTPA method is comparable to that of RQ-PCR. The iTPA method could be a reliable  and cost-effective option for the identification of MTC from broth culture.
Department of Laboratory Medicine, Konkuk University School of Medicine, Seoul, Korea.
H-W
HW
Moon
M
M
Hur
H
H
Kim
J Y
JY
Kim
C M
CM
Park
Y-M
YM
Yun
D001431:Bacteriological Techniques / Q000379:methods; D002846:Chromatography, Affinity / Q000379:methods; D003362:Cost-Benefit Analysis; D003470:Culture Media; D006801:Humans; D009169:Mycobacterium tuberculosis / Q000302:isolation & purification*; D021141:Nucleic Acid Amplification Techniques / Q000191:economics / Q000379:methods*; D016133:Polymerase Chain Reaction / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014376:Tuberculosis / Q000175:diagnosis*
D003470:Culture Media