Can aerosols of mycobacteria cause hypersensitivity pneumonitis?

This paper describes an another outbreak of hypersensitivity pneumonitis with 3 index cases where a study of the workforce identified a further 3. The metalworking fluid from a common sump was found to be heavily contaminated with bacteria including Mycobacteria. Phylogenetic analysis of high-quality HSP65 gene Sanger sequences from metalworking fluid samples grouped tightly with a representative sequence from a distinct slow-growing M. avium type strain. Unlike some other outbreaks of metalworking fluid HP attributed to mycobacteria, only weak precipitating antibodies to the used metalworking fluid were found in only 2/5 cases (and no exposed controls). No specific challenges were reported. This study falls short of identifying the mycobacteria as the cause of the HP, but does suggest that they might be. It further questions the role of precipitating antibodies in identification of cases of metalworking fluid HP

References

	James PL, Cannon J, Barber CM, Crawford L, Hughes H, Jones M, Szram J, Cowman S, Cookson WOC, Moffatt MF, Cullinan P, Metal worker’s lung: spatial association with Mycobacterium avium , Thorax, 2018;73:151-156,http://dx.doi.org/10.1136/thoraxjnl-2017-210226

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