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Comparative Study
. 2015 Nov 24;10(11):e0143025.
doi: 10.1371/journal.pone.0143025. eCollection 2015.

Comparative Study of a Real-Time PCR Assay Targeting senX3-regX3 versus Other Molecular Strategies Commonly Used in the Diagnosis of Tuberculosis

Rocio Sanjuan-Jimenez  1 , Inmaculada Toro-Peinado  2 , Pilar Bermudez  2 , Juan D Colmenero  3 , Pilar Morata  1
Affiliations
Comparative Study

Comparative Study of a Real-Time PCR Assay Targeting senX3-regX3 versus Other Molecular Strategies Commonly Used in the Diagnosis of Tuberculosis

Rocio Sanjuan-Jimenez et al. PLoS One. .

Abstract

Background: Nucleic acid amplification tests are increasingly used for the rapid diagnosis of tuberculosis. We undertook a comparative study of the efficiency and diagnostic yield of a real-time PCR senX3-regX3 based assay versus the classical IS6110 target and the new commercial methods.

Methods: This single-blind prospective comparative study included 145 consecutive samples: 76 from patients with culture-confirmed tuberculosis (86.8% pulmonary and 13.2% extrapulmonary tuberculosis: 48.7% smear-positive and 51.3% smear-negative) and 69 control samples (24 from patients diagnosed with non-tuberculous mycobacteria infections and 45 from patients with suspected tuberculosis which was eventually ruled out). All samples were tested by two CE-marked assays (Xpert®MTB/RIF and AnyplexTM plus MTB/NTM) and two in-house assays targeting senX3-regX3 and the IS6110 gene.

Results: The detection limit ranged from 1.00E+01 fg for Anyplex, senX3-regX3 and IS6110 to 1.00E+04 fg for Xpert. All three Xpert, senX3-regX3 and IS6110 assays detected all 37 smear-positive cases. Conversely, Anyplex was positive in 34 (91.9%) smear-positive cases. In patients with smear-negative tuberculosis, differences were observed between the assays; Xpert detected 22 (56.41%) of the 39 smear-negative samples, Anyplex 24 (61.53%), senX3-regX3 28 (71.79%) and IS6110 35 (89.74%). Xpert and senX3-regX3 were negative in all control samples; however, the false positive rate was 8.7% and 13% for Anyplex and IS6110, respectively. The overall sensitivity was 77.6%, 85.7%, 77.3% and 94.7% and the specificity was 100%, 100%, 90.8% and 87.0% for the Xpert, senX3-regX3, Anyplex and IS6110 assays, respectively.

Conclusion: Real-time PCR assays targeting IS6110 lack the desired specificity. The Xpert MTB/RIF and in-house senX3-regX3 assays are both sensitive and specific for the detection of MTBC in both pulmonary and extrapulmonary samples. Therefore, the real time PCR senX3-regX3 based assay could be a useful and complementary tool in the diagnosis of tuberculosis.

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Conflict of interest statement

Competing Interests: The authors have declared no competing interests exist.

Figures

Fig 1
Fig 1. Inclusion process for sample selection.
Fig 2
Fig 2. Standard curves of different assays.
Fig 3
Fig 3. The mean values of Ct of positive TB samples by different assays.
Other samples included CSF, lymph node and urine.
Fig 4
Fig 4. The DNA concentrations and purity of different clinical samples.
Other samples included CSF, lymph node and urine.
See this image and copyright information in PMC

References

    1. World Health Organization. Global tuberculosis report 2014. WHO/HTM/TB/2014.23. Available:http://apps.who.int/iris/bitstream/10665/137094/1/9789241564809_eng.pdf?....
    1. Behr MA, Warren SA, Salamon H, Hopewell PC, Ponce de Leon A, Daley CL, et al. Transmission of Mycobacterium tuberculosis from patients smear negative for acid-fast bacilli. Lancet 1999;353: 444–449. - PubMed
    1. Sarmiento OL, Weigle KA, Alexander J, Weber DJ, Ammerman AS. Assessment by meta-analysis of PCR for diagnosis of smear-negative pulmonary tuberculosis. J. Clin Microbiol. 2003;41: 3233–3240. - PMC - PubMed
    1. Getahun H, Harrington M, O'Brien R, Nunn P. Diagnosis of smear-negative pulmonary tuberculosis in people with HIV infection or AIDS in resource-constrained settings: informing urgent policy changes. Lancet. 2007;369: 2042–9. - PubMed
    1. Antonenka U, Hofmann-Thiel S, Taraev L, Esenalieva A, Abdulloeva M, Sahalchyk E, et al. 2013. Comparison of Xpert MTB/RIF with ProbeTec ET DTB and Cobas TaqMan MTB for direct detection of tuberculosis complex in respiratory specimens. BMC Infect Dis 2013;14: 280. - PMC - PubMed

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