Temporal Evolution of Urinary Microbiology Between Acute Obstructive Pyelonephritis and Delayed Ureteroscopy

Area of Science:

• Urology
• Infectious Diseases
• Medical Microbiology

Background:

• Urolithiasis frequently leads to severe infections like acute obstructive pyelonephritis (AOP).
• Urgent management of AOP involves antibiotics and urinary drainage, often with discordant urine culture results.
• The evolution of microbial pathogens between AOP and subsequent ureteroscopy is not well understood.

Purpose of the Study:

• To evaluate the concordance between bladder urine cultures (BUCap), renal pelvic urine cultures (PUCap), and preoperative bladder urine cultures (poBUC) in patients with AOP.
• To assess the clinical implications of microbiological discordance for antimicrobial management.

Main Methods:

• Retrospective single-center study of 200 patients with stone-related AOP undergoing urgent drainage and delayed ureteroscopy (2015-2025).
• Collected clinical and microbiological data, focusing on concordance between BUCap vs poBUC, PUCap vs poBUC, and BUCap vs PUCap.
• Analyzed pathogen discordance and potential impact on antimicrobial therapy.

Main Results:

• Limited concordance was observed: 55.6% (BUCap vs poBUC), 40.9% (PUCap vs poBUC), and 61% (BUCap vs PUCap).
• Pathogen discordance between AOP and poBUC was significant (50.5% for BUCap, 32.0% for PUCap).
• Antimicrobial management could have been inappropriate in 37.8-42.5% of cases if relying solely on acute-phase cultures, with overall discordance exceeding 70%.

Conclusions:

• Concordance between acute and preoperative urine cultures in AOP patients is limited.
• Preoperative urine cultures before delayed ureteroscopy are crucial.
• Microbiological findings can change substantially, necessitating updated cultures for optimal patient care.