An evaluation of bacterial urinary tract infections in patients following liver transplantation

Aim: The aim of the present study was to clinically and microbiologically investigate bacterial urinary tract infections that developed in adult patients with liver transplantations (LT) in the first year after transplantation and to retrospectively evaluate some of the risk factors that contributed to the emergence of these infections. Material and Method: Patients who underwent liver transplantations between January 1, 2015 and June 30, 2019 at the Inonu University Liver Transplant Institute were retrospectively analyzed. All adult patients (above 18 years of age) were included in the study. Bacterial urinary tract infections that developed in the first year after transplantation in adult patients with LT were discussed on the basis of clinical and microbiological data. The Centers for Disease Control and Prevention (CDC) diagnostic criteria were used in the definition and diagnosis of urinary tract infections. Patients with 105 colony forming-unit (CFU)/ml growth in urine culture analysis were included in the infected patient group. In the evaluation of the patients, infections were evaluated categorically as those occurring between 0-1 (early period) months, 1-6 (intermediate period) months, and 6-12 (late period) months post-transplantation. A 'Binary Logistic Regression' analysis was performed to determine the risk factors affecting the emergence of urinary tract infections. Results: This study examines 795 liver transplant patients that applied to the Inonu University between 2015 and 2019. While the infected group of patients included 190 patients who developed urinary tract infection attacks during the first year after transplantation, the second group examined 605 uninfected patients. Of these patients, 548 (69%) were male and 247 (31%) were female; the mean age of the patients was determined as 48.5±13.1/years. Among the causes for transplantation, hepatitis B virus (HBV) was the leading cause (34.9%) and the second was cryptogenic liver failure (25.7%). Of the liver transplantation operations, 702 (88.3%) were performed from living donors and 93 (11.7%) were performed from cadaveric donors. In this study, bacterial urinary tract infection rate was found to be 23% in the first year after transplantation. A total of 266 episodes of infection developed in 190 patients who developed infections. An assessment of the periods of occurrence of these attacks during the first year showed that attacks were most common between 1-6 months, with a rate of 38.6% between 0-1 months, 46.9% between 1-6 months, and 14.5% between 6-12 months. When the factors causing urinary system infection were examined, Escherichia coli (43.9%) was the most common microbiological agent and Klebsiella pneumoniae (28.5%) was the second most common. ESBL positivity was found to be 45.2% (53/117) and 55.2% (42/76) in Escherichia coli and Klebsiella isolates, respectively. TMP-SMX resistance, on the other hand, was found to be 71.6% (73/102) and 81.8% (44/66) in Escherichia coli and Klebsiella isolates, respectively. Advanced age, female gender and hospitalization for a duration of more than 21 days were found to increase the risk of urinary system infection (p=0.013, p<0.001, p<0.001). Conclusion: Post-transplant urinary tract infections in liver transplant patients were mostly of nosocomial origin and were most frequently detected during the first six months following transplantation. Advanced age, female gender and hospitalization for a duration of more than 21 days should be considered among the reasons that increase the risk of urinary system infections. Bacterial agents of urinary system infections and their resistance profiles in LT patients should be known and constantly monitored in each centers. Keywords: Liver transplantation, liver failure, mortality, risk factors, urinary tract infection