Drechslera, Bipolaris, and Exserohilum group

Mitosporic fungi. Hyphomycetes. Teleomorphs (sexual state): Pyrenophora, Cochliobolus, Setosphaeria (Ascomycetes).

Characteristics

Distribution

Ubiquitous;
cosmopolitan.
Some species are more commonly found in tropical or subtropical areas.
Drechslera: Approx. 20 species.
Bipolaris: Approx. 20 species.
Exserohilum: Approx. 8 species.

Where Found

Plant debris, soil. Plant pathogens of numerous plants, particularly grasses.

Mode of Dissemination

Dry spore.
Wind.

Growth Indoors

Yes, on a variety of substrates.

Industrial Uses

Not known.

Other Comments

None.

Potential Health Effects

Allergens

Common.
Type I allergies (hay fever, asthma).
Other: Most commonly reported cause of allergic fungal sinusitis.

Potential Opportunist or Pathogen

Occasionally a cause of phaeohyphomycosis, including keratitis, sinusitis, and osteomyelitis. These infections most often occur in immunocompromised persons, although infections also occur in normal hosts. One case of brain abscess reported in an immunocompromised patient.

Potential Toxin Production

Not known.

Laboratory Notes

Growth/Culture Characteristics

Grows well on general fungal media although many isolates need "light/dark cycling" for sporulation. Colonies are shades of dark gray to brown.

Spore Trap Recognition

Group includes Drechslera, Bipolaris, Exserohilum and the rare Helminthosporium. Members of this group can best be differentiated in culture.

Tape Lift Recognition

This group is readily identifiable on tape lifts.