Background: Urinary tract infections (UTIs) are the commonest infectious complication in kidney transplant recipients (KTRs). No recommendations exist regarding treatment of asymptomatic bacteriuria. We aimed to identify potential risk factors and microbiological profile for UTIs, the role of treatment of asymptomatic bacteriuria, and effects on graft outcomes of bacteriuria within the first year post-transplantation.

Methods: We performed a retrospective analysis of UTIs in KTRs transplanted between January 2012 and December 2013 in 2 transplantation centers. Patients were routinely commenced on prophylactic sulfamethoxazole-trimethoprim. Clinical and microbiological data were analyzed for the first year following transplantation.

Results: In all, 276 KTRs were evaluated; 67% were men, with a mean age of 51 years. At 12 months post-transplantation 158 (57%) KTRs had no bacteriuria, 75 (27%) had asymptomatic bacteriuria, 21 (8%) had symptomatic UTIs without further complication, and 22 (8%) with UTIs developed either pyelonephritis or urosepsis. Most frequent pathogens identified were Enterococcus faecalis and Escherichia coli, and 36% of organisms were multidrug resistant. Female sex was a risk factor for infection (P = .002), and presence of a double-J ureteral stent significantly increased the risk of asymptomatic bacteriuria and symptomatic UTIs (P = .003). Diabetes, age, and prior transplantation did not increase risk. Presence of infection was not associated with increased rejection, with similar renal function at 12 months. For episodes of bacteriuria (n = 420, asymptomatic n = 324), untreated asymptomatic bacteriuria (n = 185) followed by symptomatic UTI with the same organism was significantly higher (P = .002) compared with cases of treated asymptomatic bacteriuria (n = 139).

Conclusion: Bacteriuria post-kidney transplantation is common, affecting nearly half of KTRs in the first year after transplantation. Treatment of asymptomatic bacteriuria may be beneficial to prevent subsequent episodes of symptomatic UTIs.