Distribution
Ubiquitous;
cosmopolitan.
Approx. 12 species.
Where Found
Forest and cultivated soils, decaying fruits and vegetables, animal dung and compost; a parasitic plant pathogen on potato, cotton and various fruits.
Mode of Dissemination
Dry spore.
Wind.
Growth Indoors
Found on a variety of substrates. Common on spoiling food; less common on indoor environmental surfaces.
Aw=0.93 (R. stolonifera).
Industrial Uses
Used in cheese production, fermentation of various foods, for the production of alcohol and organic acids, and in paper production.
Other Comments
None.
Allergens
Major.
Type I allergies (hay fever, asthma).
Type III hypersensitivity pneumonitis: Paprika splitter's lung, Wood trimmer's lung.
"Sawmill lung" (an extrinsic allergic alveolitis) has been described from Swedish sawmills.
Potential Opportunist or Pathogen
Rhizopus is the principal cause of zygomycosis, which occurs primarily in patients suffering from diabetic ketoacidosis (rhinocerebral disease), malnutrition, severe burns, or who are immunocompromised.
Potential Toxin Production
Not known.
Growth/Culture Characteristics
Grows well on general fungal media; frequently fills the petri dish. Rhizopus species may overgrow and inhibit other fungi. Some structures are visible to the naked eye, i.e. sporangia appear macroscopically as black dots in the midst of white, cottony mycelia.
Spore Trap Recognition
Distinctive, identifiable on spore trap slides. Some species produce spores which are angular and faintly pigmented with striations.
Tape Lift Recognition
The presence of zygomycetes is easily noted on tape lifts. Rhizopus is distinctive, readily identifiable, if rhizoids and all sporulating structures are clearly visible.