NEW YORK (Reuters Health) - Microsporidiosis can rarely be transmitted through solid organ transplantation, according to a report from the Microsporidia Transplant Transmission Investigation Team.
"The diagnosis of microsporidiosis requires a high index of suspicion and can be difficult to make," Dr. Susan N. Hocevar from the Centers for Disease Control and Prevention in Atlanta, Georgia told Reuters Health. "Microsporidiosis should be considered in the differential diagnosis especially when other, more commonly encountered illnesses have been ruled out or when recipients are poorly responsive to therapy."
Dr. Hocevar and colleagues investigated a cluster of three transplant recipients with fever beginning 7 to 10 weeks after receipt of organs from a common donor.
Kidney biopsy in one recipient confirmed the diagnosis as microsporidiosis with Encephalitozoon cuniculi. The investigators confirmed the diagnosis with the same organism in recipients of the other kidney and the lungs.
Although Brucella infection had been suspected in all three recipients, there was no immunohistochemical evidence of Brucella in the donor or in any of the cases, the authors said in a report online February 18th in Annals of Internal Medicine.
The only survivor was treated with albendazole 400 mg orally twice daily, which ultimately had to be continued for six months (lasting until one year after the transplant) for resolution of urine PCR for the organism.
This represents the first recognized cluster of transplant-transmitted microsporidiosis linked to a common organ donor, the authors say.
"The identification of the specific species of the organism would likely need to occur at a research laboratory," Dr. Hocevar said. "CDC can perform this testing and coordination should occur through your state health department to transfer specimens to CDC. CDC can generally complete species identification within 24-48 hours of receiving a specimen."
"Empiric coverage would need to be considered on a case-by-case basis and CDC cannot make empiric therapy recommendations," Dr. Hocevar said. "Because transplant patients have a complex immunosuppressant regimen and certain medications may interact with immunosuppressants, consultation with a transplant infectious disease specialist should occur."
"Physicians should consider donor-derived disease in their transplant recipients," Dr. Hocevar concluded. "If donor derived disease is suspected, reporting to the organ procurement organization will aid in recognition of illness clusters and, when a specific organism is identified, may aid in the therapy of other organ recipients who received organs from the same donor."
"Given the diagnostic challenges and potential severity of illness with disseminated microsporidiosis, there have probably been additional undiagnosed infections and deaths," writes Dr. Camille Nelson Kotton from Massachusetts General Hospital in an editorial.
"This case and its subsequent detailed evaluation exemplify the vulnerability of organ transplant recipients, the unexpected and stealthy pathogens that may cause donor-derived infection, the importance of early reporting and excellent communication across different groups, and the power of such evaluations to initiate treatment and save lives," Dr. Kotton concludes.
"With recent advances in diagnostic technology, we soon may be able to test for more pathogens in donors, hopefully resulting in fewer 'transplant surprises,'" she added. "In the meantime, we all need to be cognizant of the stealthy pathogens that can infect our transplant patients."
Ann Intern Med 2014;160:213-220,282-283.
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