Risk Factors for Recurrent Urinary Tract Infection in Kidney Transplant Recipients

Abstract

Introduction: Urinary tract infections (UTI) are the most common infectious complication in kidney transplant recipients (KTRs). This study aims to investigate the risk factors and causative organisms of UTI and evaluate the effect of UTI on allograft function in KTRs. Methods: We analyzed the patients who underwent kidney transplantation between January 2000 and December 2010. Among a total of 344 KTRs, 50 (14.5%) patients had 106 UTI episodes during mean follow-up period of 35.9±26.0 months. Twenty-three recurrent UTI patients (recurrent group) were compared with twenty-seven non-recurrent UTI patients (non-recurrent group). Results: Renal calculi were significantly higher in recurrent group compared to non-recurrent group (43.5 vs. 7.4%, p=0.003). Diabetes mellitus, benign prostate hypertrophy and vesicoureteral reflux showed higher tendency in recurrent group. The most common causative organism was Escherichia coli (64.1%), followed by Enterococcus species (20.5%). The distributions of organisms were not different between the two groups. In terms of antibiotic resistance in Escherichia coli, the extended-spectrum beta-lactamase (ESBL) production was significantly higher in recurrent group than in non-recurrent group (53.1 vs. 0%, p=0.013). The estimated glomerular filtration rate (eGFR) fell from 76.7±42.3 mL/min/1.73m2 to 56.4±27.3 mL/min/1.73m2 in recurrent group (p=0.006), while eGFR fell from 68.7±26.9 mL/min/1.73m2 to 65.6±28.5 mL/min/1.73m2 in non-recurrent group (p=0.313). Conclusion: This study suggests that renal calculi are the major risk factor for recurrent UTI in KTRs. The recurrent group showed higher rates of antibiotic resistance, especially the ESBL production. The decline of eGFR was statistically significant only in recurrent group during the study period. It is reasonable to treat initial UTI adequately to prevent recurrent infection and prolong graft longevity, especially in KTRs with risk factors for recurrent UTI.