Rhizopus sp

Zygomycete

Characteristics

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.

Potential Health Effects

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.

Laboratory Notes

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.