Urinary tract infection in the renal transplant patient

Since the first successful kidney transplantations were performed in the 1950s, understanding of the factors that improve graft outcome has advanced. Nevertheless, post-transplantation urinary tract infections continue to be a source of morbidity and graft failure. This article reviews urinary tract infection in the renal transplant recipient, covering epidemiology, etiology, prevention, presentation, investigations, diagnosis and management. Urinary tract infection (UTI) is the most common type of bacterial infection contracted by recipients of renal allografts in the post-transplantation period. Fungi and viruses can also cause UTIs, but infections caused by these organisms are less common than those caused by bacteria. Both the lower and upper urinary tract (encompassing grafted or native kidneys) can be affected. Factors that might contribute to the development of UTIs include excessive immunosuppression, and instrumentation of the urinary tract (e.g. urethral catheters and ureteric stents). Antimicrobials are the mainstays of treatment and should be accompanied by minimization of immunosuppression when possible. The use of long-term antimicrobial prophylaxis is controversial, however, as it might increase the likelihood of infective organisms becoming resistant to treatment. There are conflicting data on the associations of post-transplantation UTI with graft and patient survival. Key Points Urinary tract infection (UTI) is the most common bacterial infection in the period after renal transplantation; the infection can develop early (within 6 months of the procedure) or late (more than 6 months after transplantation) Excessive immunosuppression might be a key factor in the development of both early and late UTI; early UTI might also be caused by instrumentation of the urinary tract (e.g. urethral catheters and ureteric stents) Fungal and viral infections are less common than bacterial UTIs but require active management Post-transplantation UTI should be treated with antimicrobials, and by reducing immunosuppression when appropriate Upper UTI (i.e. pyelonephritis) of either transplanted or native kidneys should be treated aggressively, and any underlying cause detected The use of long-term antimicrobial prophylaxis is controversial and could increase the risk of bacterial resistance to treatment Transplant pyelonephritis, as opposed to lower tract UTI, might be associated with decreased long-term graft function