Effectiveness of Roxithromycin for Treating Isospora belli Infection

Isospora infections are usually self-limiting and often asymptomatic. However, chronic infections associated with malabsorption, abdominal discomfort, and diarrhea have been reported in debilitated, immunodeficient patients. Some authors have demonstrated in vitro activity of roxithromycin (Roussel-UCLAF, Paris), a new macrolide, against Entamoeba histolytica and Toxoplasma gondii . Because Toxoplasma is considered a coccidia (also called "Isospora gondii "), the authors tried using roxithromycin to treat a patient with TMP-SMZ-resistant isosporiasis. The authors report here the observation of a human immunodeficiency virus (HIV)-seropositive patient with isosporiasis and leukopenia who responded favorably to treatment with roxithromycin.