Staphylococcus aureus infections in kidney transplantation: A matched case controlled study

Background: Data are lacking on the risk factors and outcomes of Staphylococcus aureus infections in kidney transplant recipients. Methods: Kidney recipients with S. aureus infections (n = 20) were retrospectively identified and compared to age-and transplant-type-matched (1:2) non-S. aureus-infected controls (n = 40). Risk factors for S. aureus infections were identified by conditional logistic regression analysis. Results: Methicillin-resistant S. aureus (MRSA) was the cause of 32.1% of infections. Localizations of the infections were as follows: skin 42.9%, intra-abdominal 35.7%, blood stream 7.1%, and pulmonary 10.7%. The infections developed at a median time of 29 days (range 0-358 days) after transplantation. By univariate analysis, variables significantly associated with infection were steroid administration 4 weeks prior to infection (odds ratio (OR) 4.2, 95% confidence interval (95% CI) 1.1-15.8; p = 0.03) and the presence of a central venous catheter 7 days prior to infection (OR 5.6, 95% CI 1.1-27.8; p = 0.03). By multivariate analysis, subjects with steroid treatment during the previous 4 weeks had a 6.13-times higher risk of developing S. aureus infection (95% CI 1.5-25.7; p = 0.01), and the risk of infection decreased by a factor of 0.65 for every 1-y increase in age (95% CI 0.44-0.97; p = 0.03); these results were adjusted for matched criteria. Post-infection outcomes (cases vs controls) included graft loss (10% vs 0%; p = 0.11) and 12-month mortality (0% vs 2.5%; p = 0.99). Conclusions: Younger age and steroid treatment were significant independent risk factors associated with S. aureus infections after kidney transplantation. Graft and patient survival were not affected, but the study was not powered for these outcomes.