Acanthamoeba

Acanthamoeba is a genus of amoebae common in soil, fresh water and many other environments worldwide, passing through an active, feeding trophozoite stage and a dormant, highly resistant cyst stage that helps it survive harsh conditions. In nature these amoebae mostly feed on bacteria, but some species can act as opportunistic pathogens, causing serious and sometimes fatal infections in humans and other animals, including a severe eye infection linked to contaminated contact lens cases and a rare but often fatal brain infection in people with weakened immune systems. Isolates of the genus have been recovered from an unusually wide range of places, including soil, water systems, dental equipment and contact lens cases.