Low sensitivity of the MPT64 identification test to detect lineage 5 of the Mycobacterium tuberculosis complex

C. N'Dira Sanoussi, Bouke C. de Jong, Mathieu Odoun, Karamatou Arekpa, Moulikatou Ali Ligali, Ousman Bodi, Simon Harris, Boatema Ofori-Anyinam, Dorothy Yeboah-Manu, Isaac Darko Otchere, Adwoa Asante-Poku, Severin Anagonou, Sebastien Gagneux, Mireia Coscolla, Leen Rigouts, Dissou Affolabi

Research output: Contribution to journalA1: Web of Science-article

Abstract

Purpose. Differentiation of the Mycobacterium tuberculosis complex (MTBc) from non-tuberculous mycobacteria (NTM) is important for tuberculosis diagnosis and is a prerequisite for reliable phenotypic drug-resistance testing. We evaluated the performance of the rapid MPT64 antigen identification test for the detection of Mycobacterium africanum lineage 5 (MAF L5).

Methodology. Smear-positive tuberculosis patients' sputa were included prospectively. Culture was performed on Lowenstein-Jensen medium and, when positive, the MPT64 test and the classical para-nitro benzoic acid susceptibility and heat-labile catalase (PNB/catalase) identification tests were performed. The MPT64 test was repeated 14 days after an initially negative first testing. Direct spoligotyping was performed for MTBc lineage determination.

Results. In total, 333 isolates were tested for all of the methods. Three hundred and twenty-two (96.7 %) were pure MTBc, by agreement between spoligotyping and PNB/catalase, and 11 were NTM or a mixture of MTBc/NTM. The MPT64 test conducted on day zero of culture-positivity correctly identified most of the pure MTBc isolates (93.2 %, 300/322), but it failed to detect 24% of the L5 isolates (18/75) versus 2% (4/202) of the L4 ones [OR=15.6 (5.3-45.8), P

Conclusion. The MPT64 test has a lower sensitivity for detecting L5 isolates of the MTBc, and can be considered as a first-screening test that should be confirmed by another identification method when it produces negative results in countries with L5. Given the microbiological bias in both the isolation and identification of MAF lineages, diagnostics with high sensitivity for direct testing on clinical material are preferable.

Original languageEnglish
JournalJournal of Medical Microbiology
Volume67
Issue number12
Pages (from-to)1718-1727
Number of pages10
ISSN0022-2615
DOIs
Publication statusPublished - 2018

Keywords

  • Rapid MPT64 identification test
  • Mycobacterium tuberculosis complex lineages
  • Mycobacterium africanum West African 1 (Lineage 5)
  • non-tuberculous mycobacteria
  • mpt64 gene (Rv1980c)
  • non-synonymous SNP
  • DIAGNOSIS

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