Aspergillus

Aspergillus is a genus of ubiquitous filamentous environmental molds whose spores are commonly found on cannabis. Four species are targeted in regulatory testing and collectively designated "pathogenic Aspergillus": A. fumigatus (the most common cause of invasive aspergillosis), A. flavus (produces aflatoxins), A. niger (causes otomycosis and pulmonary aspergillosis), and A. terreus (often amphotericin-B resistant). While healthy individuals generally tolerate Aspergillus inhalation, invasive pulmonary aspergillosis can be rapidly fatal in immunocompromised patients — HIV/AIDS, transplant recipients, chemotherapy patients, those on corticosteroids, and cystic fibrosis patients — many of whom are medical cannabis users. Mortality exceeds 50% even with antifungal treatment. qPCR is strongly preferred over culture-based detection because Aspergillus grows slowly on culture media, forms heterogeneous macrocolonies that clump, and is overgrown by competitive flora, causing false negatives. Multiplex qPCR assays (Medicinal Genomics PathoSEEK, GT Molecular, Applied Food Diagnostics) detect all four species plus an internal control in one reaction. Aspergillus testing is mandatory for inhalable products in California, Colorado, Michigan, Nevada, Massachusetts, Oregon, Washington, New York, New Jersey, and Florida, though some states (Maine historically, Oklahoma) rely on TYM counts instead. → See also: Microbial testing, Mycotoxin, Testing lab