Limited utility of blood cultures in the management of febrile outpatient kidney transplant recipients

Background/Purpose Blood cultures for patients suspected of having bacteremia are standard practice, although several studies demonstrate that blood cultures have limited utility because of a low true-positive rate and infrequent resultant changes in antibiotic treatment. However, most reports exclude immunocompromised patients such as transplant recipients. We assessed the utility of blood cultures in transplant recipients hospitalized for community-acquired infections and evaluated clinical characteristics to predict bacteremia. Methods This retrospective study included 136 febrile cases in 97 kidney transplant recipients admitted to our hospital for whom blood cultures were performed between February 2001 and March 2013. Results Among the 136 cases, blood cultures were positive, contaminated, and negative in seven (5.1%) cases, 12 (8.8%) cases, and 117 cases (86.1%), respectively. All bacteria detected in the seven cases were sensitive to the initial empirical antibiotics. Antibiotic treatment was changed based on the blood culture results only in one case for which the coverage was narrowed. The white blood cell count and C-reactive protein level were significantly higher in the patients with bacteremia. The predictive model based on these two factors successfully identified the high-risk group with a sensitivity and specificity of 86% and 91%, respectively. Conclusion Among the outpatient kidney transplant recipients, positive blood cultures were uncommon and scarcely affected antibiotic therapy, especially in patients with upper respiratory tract or urinary tract infections. Therefore, it may be reasonable to perform blood cultures only for patients with marked leukocytosis and high C-reactive protein level, even among transplant recipients.