Successful treatment of Enterocytozoon bieneusi gastrointestinal infection with nitazoxanide in a immunocompetent patient

Microsporidia are organisms that are known to cause opportunistic infections in immunocompromised individuals. The gastrointestinal tract is the most common affected organ. Enterocytozoon bieneusi is the most common species that infect humans. There are no known established guidelines for the treatment of this particular microsporidium. A 72-year old immunocompetent female presented to our hospital with diarrhea for four weeks. She had failed outpatient oral antimicrobial treatment for suspected traveler’s diarrhea and Clostridium difficile. Initial stool cultures were negative but given her persistent symptomatology, stool PCR was sent to rule out microsporidia and was positive for Enterocytozoon bieneusi. Patient failed treatment with albendazole. She was then subsequently treated with nitazoxanide and achieved successful infection resolution. This case demonstrates the importance of considering atypical infections in patient with persistent symptoms and suggest that nitazoxanide is effective in treating infection caused by Enterocytozoon bieneusi microsporidia.