[Citrobacter freundii endocarditis].

Infection by Citrobacter appears in man only in certain circumstances, since it usually acts as contaminant or colonizer. Bacteraemia by this bacillus can affect immunodeficient people, elderly people or those patients who have undergone invasive hospital processes. Although incidence of bacteraemia is low (0.3-0.9%), the death rate is very high, about 48%. This bacillus is seldom the cause of endocarditis. That is why we describe a case of endocarditis by Citrobacter freundii, in an aged person with previous valvulopathy.