Nocardial infection in immunosuppressed kidney transplant recipients

Objective: Nocardiosis is a very rare, opportunistic infection caused by microorganisms of the genus Nocardia, and is associated with significant morbidity and mortality in kidney transplant patients receiving immunosuppressive therapy. Material and Methods: Since 1980, our Renal Transplant Unit has carried out 1239 kidney transplants, and five cases of Nocardia infection have occurred during this time. In this retrospective study, special consideration is given to clinical manifestations, treatment response (efficacy and side-effects) and the evolution of both the patient and the graft. Microbiological factors studied included biochemical profiles and antimicrobial sensitivity. Results: Nocardiosis was observed in five men with a mean age of 49.2 years who had received immunosuppressive therapy (generally cyclosporin/azathioprine and prednisone) for a mean of 47.8 months (range 1-148 months). Four of the patients had good previous renal function. The clinical presentation of nocardiosis was as follows: pleuropulmonary pattern of infection, n = 3; subcutaneous abscess, n = 1; and fulminant multi-organ disseminated nocardiosis, n = 1. In all cases, direct observation using modified Ziehl-Neelsen staining proved positive, and in vitro culture revealed good sensitivity to trimethoprim-sulfamethoxazole and variable sensitivity to the other groups of antibiotics. Nocardia brasiliensis was isolated in two cases, and Nocardia asteroides in three. Two patients died, one due to multiple organ involvement and the other due to acute respiratory failure associated with severe hepatopathy caused by hepatitis C virus. The remaining cases improved. Conclusion: A low incidence of nocardiosis following kidney transplantation was observed. Fatal cases occurred in patients with bacteremia and serious comorbid medical conditions, in whom early diagnosis and specific treatment was required.