[Detection of Mycobacterium tuberculosis complex in paraffin-embedded tissues by real-time fluorescent quantitative polymerase chain reaction].
OBJECTIVE
To investigate the feasibility of real-time fluorescent quantitative (qPCR) assay in detecting mycobacterium tuberculosis complex (MTB) in paraffin embedded tissues for diagnostic purpose.


METHODS
Using qPCR assay, 1000 consecutive formalin-fixed and paraffin embedded (FFPE) tissues (from 2011 to 2012) suspected of MTB infection were tested by amplifying the MTB specific insertion sequence 6110 (IS6110). The specificity of the PCR product was confirmed by Sanger sequencing as compared with the MTB genomic DNA of the IS6110 sequence. Tissues with Ziehl-Neelsen acid-fast staining were used as control.


RESULTS
In the 1000 samples, 513 were positive for mycobacterium by Ziehl-Neelsen acid-fast staining (detection rate 51.3%); whereas 546 were MTB positive by qPCR assay (detection rate 54.6%). Concordance rate for both assays was 73.1%. The diagnosis rate increased by 14.4% by combinination of Ziehl-Neelsen acid-fast staining and qPCR results. More interestingly, by analyzing the Ziehl-Neelsen acid-fast staining and qPCR results three cases of M.leprae infection and four cases of non-tuberculous Mycobacterium (NTM) infection were identified.


CONCLUSIONS
qPCR detection of MTB in FFPE tissue is more sensitive than Ziehl-Neelsen acid-fast staining assay. Combination of these two assays can increase the detection rate and also identify some rare cases of NTM infection.
Department of Pathology, West China Hospital, Sichuan University, Chengdu 610041, China.
Feng
F
Ye
Yu
Y
Chen
Du
D
He
Shu-yu
SY
Jian
Ke
K
Zheng
Gan-di
GD
Li
Hong
H
Bu
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D004269:DNA, Bacterial / Q000235:genetics; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009169:Mycobacterium tuberculosis / Q000235:genetics / Q000302:isolation & purification*; D016612:Paraffin Embedding; D060888:Real-Time Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D013194:Staining and Labeling / Q000379:methods; D014376:Tuberculosis / Q000175:diagnosis* / Q000382:microbiology; D014385:Tuberculosis, Gastrointestinal / Q000175:diagnosis / Q000382:microbiology; D014388:Tuberculosis, Lymph Node / Q000175:diagnosis / Q000382:microbiology; D014397:Tuberculosis, Pulmonary / Q000175:diagnosis / Q000382:microbiology; D055815:Young Adult
D004269:DNA, Bacterial