A case of Enterocytozoon bieneusi infection in an HIV-negative renal transplant recipient

Reported here is a case of microsporidiosis that occurred in an HIV-negativ e renal transplant recipient. The patient developed protracted diarrhea 18 months following transplant surgery. Many spores of Enterocytozoon bieneusi were detected in stool smears using a modified trichrome staining method. Identification was confirmed using the polymerase chain reaction. Histologi cal examination of duodenal biopsies revealed numerous spores in the cytopl asm of enterocytes. Tacrolimus and steroid regimens were decreased, treatme nt with mycophenolate mofetil was discontinued, and the patient was given a lbendazole and metronidazole for 2 weeks. The diarrhea resolved after 15 da ys of treatment; 2 months later the patient had recovered completely. A mor e systematic search for microsporidia using specific staining procedures sh ould be performed in transplant recipients who develop severe diarrhea.