Blood samples and urine cultures will be obtained from asymptomatic renal transplant clinic patients. If the urine culture is positive (> or = 105 cfu/ml), we will determine the host and bacterial virulence factors associated with asymptomatic bacteriuria (ASB) and compare these results to transplant patients that develop a symptomatic UTI. The patient's clinical information, laboratory data and the bacterial isolate responsible for the UTI will be collected at the time of their clinic visit and subsequently analyzed.