Symptomatic respiratory Encephalitozoon cuniculi infection in renal transplant recipients.

OBJECTIVES: Encephalitozoon spp. and Enterocytozoon bieneusi are intracellular parasitic fungi from the phylum Microsporidia, which initially localize to intestine. As opportunistic pathogens, especially Encephalitozoons can disseminate, among others to the respiratory tract. Patients under life-long immunosuppression are at higher risk of such infections, mostly symptomatic.

METHODS: Sputum samples and bronchial washings from 72 renal transplant recipients and 105 patients with various respiratory diseases were screened for Encephalitozoon spp. and E. bieneusi by microscopic examination and genus-specific nested PCR followed by genotyping.

RESULTS: A total of 8.3% (6/72) of immunosuppressed renal transplant recipients and 1.9% (2/105) of patients with various respiratory diseases both immunocompetent and immunosuppressed were positive for respiratory microsporidial infection. All six transplant recipients were Encephalitozoon cuniculi positive by PCR/sequencing and five of them suffered from respiratory symptoms. In three of the transplant recipients presence of microsporidial spores was also confirmed microscopically. Of the two immunocompetent patients with various respiratory diseases one had E. cuniculi while the second had E. bieneusi infection.

CONCLUSIONS: Life-long immunosuppression in renal transplant recipients increases the risk of respiratory infection by E. cuniculi. Microsporidia should be screened in respiratory samples of this kind of patients, particularly when they have respiratory symptoms.