Target-specific assay for rapid and quantitative detection of Mycobacterium chimaera DNA

Enrique Zozaya-Valdés, Jessica L. Porter, John Coventry, Janet A.M. Fyfe, Glen P. Carter, Anders Gonçalves Da Silva, Mark B Schultz, Torsten Seemann, Paul D.R. Johnson, Andrew J. Stewardson, Ivan Bastian, Sally A. Roberts, Benjamin P. Howden, Deborah A. Williamson, Timothy P. Stinear

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14 Citations (Scopus)


Mycobacterium chimaera is an opportunistic environmental mycobacterium belonging to the Mycobacterium avium-M. intracellulare complex. Although most commonly associated with pulmonary disease, there has been growing awareness of invasive M. chimaera infections following cardiac surgery. Investigations suggest worldwide spread of a specific M. chimaera clone, associated with contaminated hospital heater-cooler units used during the surgery. Given the global dissemination of this clone, its potential to cause invasive disease, and the laboriousness of current culture-based diagnostic methods, there is a pressing need to develop rapid and accurate diagnostic assays specific for M. chimaera. Here, we assessed 354 mycobacterial genome sequences and confirmed that M. chimaera is a phylogenetically coherent group. In silico comparisons indicated six DNA regions present only in M. chimaera. We targeted one of these regions and developed a TaqMan quantitative PCR (qPCR) assay for M. chimaera with a detection limit of 100 CFU/ml in whole blood spiked with bacteria. In vitro screening against DNA extracted from 40 other mycobacterial species and 22 bacterial species from 21 diverse genera confirmed the in silico-predicted specificity for M. chimaera. Screening 33 water samples from heater-cooler units with this assay highlighted the increased sensitivity of PCR compared to culture, with 15 of 23 culture-negative samples positive by M. chimaera qPCR. We have thus developed a robust molecular assay that can be readily and rapidly deployed to screen clinical and environmental specimens for M. chimaera.

Original languageEnglish
Pages (from-to)1847-1856
Number of pages10
JournalJournal of Clinical Microbiology
Issue number6
Publication statusPublished - 1 Jun 2017
Externally publishedYes


  • Diagnostics
  • Genomics
  • Infectious disease
  • Mycobacterium

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