The eperythrozoon are a group of related bacteria that do not have a cell wall. They are part of a family of similar bacteria known as the mycoplasma. They rarely infect humans, but can cause anemia in mice and pigs.
Although the eperythrozoon rarely cause disease in humans, treatment of an infected individual is complicated by the fact that penicillin and similar antibiotics do not affect eperythrozoon because those antibiotics attack bacteria by destroying the cell wall that is absent in mycoplasma bacteria. As such, streptomycin or other similar antibiotics are the only effective choice.