Asymptomatic bacteriuria and urinary tract infections among renal allograft recipients

Bacteriuria is common among renal allograft recipients. It can be categorized into asymptomatic bacteriuria (ASB) and urinary tract infection (UTI). However, in medical literature, the classifications of bacteriuria are often not clear or ASB is also classified as a UTI. This contributes to difficulties in interpretation of the incidence and risk factors of these two entities. In this review, we describe the epidemiology, risk factors, management and the impact on renal allograft function of these two entities separately according to the recent literature. Risk factors for ASB are not completely comparable to the risk factors of UTIs. Persistent ASB has been associated with development of acute rejection and allograft pyelonephritis. The available data suggest that treatment of ASB is not very effective. Prophylaxis with trimethoprim-sulfamethoxazole does not prevent UTIs such as allograft pyelonephritis. Blood stream infections and emphysematous allograft pyelonephritis are associated with renal allograft loss. ASB is the most common manifestation of bacteriuria after renal transplantation. More effective interventions are needed to prevent bacteriuria. Renal allograft recipients with persistent ASB should be closely monitored since they could be at risk for developing not only UTIs, such as allograft pyelonephritis, but also acute rejection