Blastomyces dermatitidis screen, bulk samples (qualitative) (PCR) [BLASTO]

Published: July 8th, 2009

Revised: April 19th, 2023

Blastomyces is a genus of dimorphic fungi that can cause a disease called blastomycosis in humans and other animals. Species of Blastomyces exist in the environment in a filamentous form and can produce infectious spores that can be inhaled. Once inside the body, the spores transform into yeast-like cells that can cause localized or disseminated infections. Blastomycosis primarily affects the lungs but can also involve other organs such as the skin, bones, and central nervous system. The disease is endemic in certain regions of North America, particularly in the Mississippi River and Great Lakes regions, and is more common in males than females. Two species are predominantly implicated as etiologic agents of this disease: B. dermatitidis and B. gilchristii. Both appear to be widespread throughout the endemic zone in North America.

This test expands on work conducted by Professor Tom Volk (now deceased) from the University of Wisconsin-Lacrosse. The procedure targets a portion of the virulence gene promotor, appropriately named BAD1 using conventional PCR. The results are reported as presence or absence of B. dermatitidis and B. gilchristii. A range of sample types can be analysed including dusts, bulk materials, and large volume air samples. In our experience, Blastomyces is extremely difficult to detect in environmental samples, and it seems likely that DNA of species of Blastomyces is highly ephemeral. As a consequence, this test is really only useful when an outbreak has been identified in humans or animals (especially dogs) as a means to assist in elucidating the nature of the exposure and reservoir. Even then, the timing of sampling must be as close as possible to the event in order to maximize the potential to yield informative positive results.

Laboratory code: BLASTO

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