Microbiology Series: Fifth in a Six-Part Series
Alternaria

photo-6icMendicembers of the genus Alternaria are occasionally associated with human infection. They have been reported to produce human bone infections, skin infections, and infections of the urinary tract, ears and eyes.¹ The most likely Alternaria species to produce an infection in humans is Alternaria alternata.² Alternaria colonies are very large on agar plates and can be light gray or dark black in color. They appear like cotton or wool on Petri dishes and the reverse side of the colony is black.

The organism is usually isolated from plants and soil in nature. It is not …