UROPOT: study protocol for a randomized, double-blind phase I/II trial for metabolism-based potentiation of antimicrobial prophylaxis in the urological tract

BACKGROUND

Urinary tract catheters, including Double-J or ureteral stents, are prone to bacterial colonization forming biofilms and leading to asymptomatic bacteriuria. In the context of asymptomatic bacteriuria, endourological procedures causing mucosa-inducing lesions can lead to severe infections. Antibiotic prophylaxis is warranted, yet its efficacy is limited by biofilm formation on stents. Biofilms promote antibiotic tolerance, the capacity of genetically susceptible bacteria to survive a normally lethal dose of antimicrobial therapy. The UROPOT study evaluates the effectiveness of a first-in-type metabolism-based aminoglycoside potentiation for (i) preventing infectious complications of asymptomatic bacteriuria during mucosa lesion-inducing endourological procedures and (ii) assessing its anti-tolerance efficacy.

METHODS

The UROPOT trial is a phase I/II single-center (Lausanne University Hospital (CHUV), Switzerland) randomized double-blinded trial. Over 2 years, patients with asymptomatic Escherichia coli and/or Klebsiella pneumoniae bacteriuria, undergoing endourological procedures, will be randomly allocated to one of three treatment arms (1:1:1 randomization ratio, 30 patients per group) to evaluate the efficacy of mannitol-potentiated low-dose amikacin compared to established standard treatments (ceftriaxone or amikacin standard dose). Patients will be recruited at the CHUV Urology Outpatient Clinic. The primary outcome is the comparative incidence of postoperative urinary tract infections (assessed at 48 h) between the investigational amikacin/mannitol therapy and standard (ceftriaxone or amikacin) antibiotic prophylaxis, defined by specific systemic symptoms and/or positive blood and/or urine culture. Secondary outcomes include assessing microbiological eradication through anti-biofilm activity, sustained microbiological eradication, and mannitol and antibiotics pharmacokinetics in blood and urine. Safety outcomes will evaluate the incidence of adverse events following amikacin/mannitol therapy and postoperative surgical complications at postoperative day 14.

DISCUSSION

UROPOT tests a novel antimicrobial strategy based on "metabolic potentiation" for prophylaxis enabling aminoglycoside dose reduction and targeting biofilm activity. The anti-biofilm effect may prove beneficial, particularly in patients who have a permanent stent in situ needing recurrent endourological manipulations strategies in preventing infections and achieving sustained microbiological eradication in pre-stented patients.

TRIAL REGISTRATION

The protocol is approved by the local ethics committee (CER-VD, 2023-01369, protocole 2.0) and the Swiss Agency for Therapeutic Products (Swissmedic, 701,676) and is registered on the NIH's ClinicalTrials.gov (trial registration number: NCT05761405). Registered on March 07, 2023.

Urinary tract infections after retrograde pyelography and prophylactic antibiotics

INTRODUCTION

Retrograde pyelography (RP) is performed for examination of upper urinary tract cancers and hydronephrosis. Although urinary tract infections (UTI) are known to be complicated by the examination, there are few reports on the frequency of occurrence and prophylactic antibiotics.

METHODS

The incidence of UTI and febrile UTI (f-UTI) and patient background information were compared in 388 patients who underwent RP at our hospital from January 2018 to December 2022. We also examined the administration of pre-RP antibiotics.

RESULTS

Of the 388 patients who underwent RP, 27 (6.9%) had UTI and 17 (4.4%) had f-UTI. Of the 27 UTI cases, 25 (92.6%) were pyelonephritis; 20 (74.0%) were hospitalized and 2 (7.4%) presented with septic shock and were managed in the intensive care unit. When comparing the background of patients with UTI, no significant differences were found in the present study, but when limited to the 17 cases of f-UTI, the presence of hydronephrosis before RP and not prescribing antibiotics before RP were associated with significantly higher incidence of f-UTI (p = 0.019, p = 0.036, respectively). Especially for patients without pyuria and bacteriuria before RP, prescribing antibiotics before RP resulted in 0 cases of f-UTI (p = 0.020).

CONCLUSION

This retrospective study showed that the presence of hydronephrosis before RP and not prescribing prophylactic antibiotics before RP are risk factors for f-UTI.

Retrospective Analysis of the Role of Antibiotic Prophylaxis in the Placement and Replacement of Percutaneous Nephrostomy Catheters in Patients with Malignant Ureteral Obstruction

Background: Antibiotic prophylaxis is usually adopted to prevent urinary tract infection (UTI) after nephrostomy catheter placement and replacement. This prophylaxis has been little studied in cancer patients, and its efficacy is uncertain. Objective: To determine the rate of UTI associated with percutaneous nephrostomy catheters placement and replacement and associated risk factors. Methods: This retrospective study collected data from the available medical records. Catheter-related UTI was defined as any diagnosis of UTI based on clinical symptoms recorded in antibiotic prescription charts, and on the results of urine culture collected up to 7 days after percutaneous nephrostomy catheter. The associations between categorical variables were analyzed using Fisher's exact test. The risk factors for UTI were assessed using logistic regression. Results: In the univariate analyses, there was no significant difference in the rate of urinary infection between patients receiving and not receiving antibiotic prophylaxis before percutaneous nephrostomy and after replacement. Conclusion: The results of the present study suggest that the use of antibiotic prophylaxis for managing urinary tract obstruction by percutaneous nephrostomy is not recommended in cancer patients. In contrast, for catheter replacement, antibiotic prophylaxis appears to have a protective effect for UTI.