Metal worker's lung: spatial association with Mycobacterium avium

Area of Science:

• Occupational Health
• Microbiology
• Environmental Health

Background:

• Hypersensitivity pneumonitis (HP) outbreaks are linked to metal working fluid (MWF) use.
• Previous studies lacked spatial links between MWF contamination and HP outbreaks.
• Metalworking environments pose risks for respiratory diseases.

Purpose of the Study:

• Investigate an HP outbreak in a UK factory.
• Identify microbial culprits and their sources in metal working fluid.
• Establish spatial relationships between microbial contamination and HP cases.

Main Methods:

• Blinded, molecular-based microbiological investigation of MWF samples.
• Custom-quantitative PCR assays for microbial quantification.
• Microscopy and phylogenetic analyses for microbial identification.

Main Results:

• Mycobacteria contamination found in MWF from a central sump, not isolated supplies.
• High levels of organisms detected in the factory sump and a linked machine.
• Phylogenetic analysis identified organisms closely related to Mycobacterium avium.

Conclusions:

• First documented spatial link between Mycobacterium avium in MWF and a localized HP outbreak.
• Sequence-based techniques can aid prevention of occupational HP.
• Contaminated MWF is a significant risk factor for hypersensitivity pneumonitis.