Antibiotic resistance of urinary pathogens after kidney transplantation: a 10-year single-center survey in Germany.

Purpose: Urinary tract infections (UTIs) are common complications after kidney transplantation (KT), often resulting in severe outcomes like acute graft failure and sepsis. Factors such as diabetes, age, sex, and type of transplantation significantly influence disease progression. Rising antibiotic resistance complicates treatment, emphasizing the importance of Antimicrobial Stewardship (AMS), particularly during the post-transplant immunosuppression phase. Recent changes in treatment protocols, including a shift away from treating asymptomatic bacteriuria and modifications in antibiotic prescribing, highlight the need for updated resistance trend analyses.

Methods: This retrospective study at the University Hospital Essen analyzed urine samples from kidney transplant outpatients from 2013 to 2022. Pathogen identification and resistance testing focused on common UTI pathogens, including Escherichia coli, Klebsiella spp., Pseudomonas aeruginosa, Enterococcus faecium, and Enterococcus faecalis. Data on antibiotic prescriptions were sourced from the North Rhine Association of Statutory Health Insurance since 2017.

Results: Out of 10,508 urine samples collected from 6962 patients, bacterial growth was detected in 4126 samples (39%). Escherichia (E.) coli was the most frequent pathogen (41%). Klebsiella spp., which accounted for 11.7% of all pathogens, showed increasing resistance to piperacillin/tazobactam and ceftazidime. Resistance rates Enterococcus faecalis showing a significant decline in levofloxacin (100% resistance in 2014 in all isolates, compared to 2% in 2022). An increasing concern in our cohort is the prevalence of Extended Spectrum Beta-Lactamase (ESBL)-producing Gram-negative pathogens, particularly Klebsiella spp., which are being detected with greater frequency. In our center, we have observed a significant increase in the use of oral antibiotics recommended for first-line therapy. This shift is attributed to updated guidelines and therapeutic recommendations. Consequently, oral cephalosporins are now rarely used due to their low bioavailability.

Conclusion: The study highlights the importance of ongoing surveillance to address antibiotic resistance in KT recipients. Increasing resistance in pathogens like Klebsiella spp. necessitates new antimicrobial strategies. Findings should inform future guidelines to preserve antibiotic effectiveness and improve therapeutic outcomes in this vulnerable patient population.