title: Implementation of a quantitative real-time PCR assay for the detection of Mycobacterium immunogenum in metalworking fluids.
abstract: The bacterium Mycobacterium immunogenum has been implicated in causing the lung condition hypersensitivity pneumonitis (HP) in factory workers exposed to colonized metalworking fluids (MWFs). M. immunogenum-specific, real-time quantitative PCR detection technique (MiRT-qPCR) was implemented on a large scale to 363 MWFs of varying types, originating from the United States and Europe, that had been in use for between 30 days and 1 year. In MWFs that contained between 10(3) and 10(9) culturable general heterotrophs mL(-1) the technique detected between 5 and 2 × 10(6) mL(-1) M. immunogenum cell equivalents (CE) in 12.2% (23 of 189) of U.S. samples and between 8 and 6 × 10(5) mL(-1) CE in 39.1% (68 of 174) of samples from Europe. In contrast, only three cultured presumptive mycobacterial isolates across all samples were confirmed as M. immunogenum. Implementation of the assay demonstrated its practicality and further emphasized the limitations of using cultivation alone. Interestingly, no M. immunogenum were detected in mineral oil-based Bio-Concept MWFs from the United States, while it was more commonly detected in used MWFs based on formaldehyde-releasing biocides than in MWFs free of formaldehyde-depot biocides.
authors.affiliation: Centre for Ecology and Hydrology, Lancaster Environment Centre, Bailrigg, Lancaster, UK. glenn@ceh.ac.uk
authors.forename: Glenn
authors.initials: G
authors.lastname: Rhodes
authors.forename: Alexandra
authors.initials: A
authors.lastname: Fluri
authors.forename: Andrea
authors.initials: A
authors.lastname: Ruefenacht
authors.forename: Marco
authors.initials: M
authors.lastname: Gerber
authors.forename: Roger
authors.initials: R
authors.lastname: Pickup
mesh_terms: D000542:Alveolitis, Extrinsic Allergic / Q000382:microbiology / Q000517:prevention & control; D015169:Colony Count, Microbial; D004269:DNA, Bacterial / Q000235:genetics; D004783:Environmental Microbiology; D004784:Environmental Monitoring; D006801:Humans; D007219:Industrial Oils / Q000382:microbiology*; D008669:Metallurgy; D009165:Mycobacterium Infections, Nontuberculous / Q000382:microbiology / Q000517:prevention & control; D009170:Nontuberculous Mycobacteria / Q000235:genetics / Q000302:isolation & purification*; D016133:Polymerase Chain Reaction / Q000379:methods*
chemical_list: D004269:DNA, Bacterial