Infection Risk in Patients with Mixed Flora in Urine Cultures Prior to Ureteroscopy

Area of Science:

• Urology
• Infectious Diseases
• Medical Microbiology

Background:

• Urine cultures guide antibiotic use before endourologic surgery.
• The significance of mixed flora in preoperative urine cultures is unclear.
• This study investigates infectious outcomes in patients with mixed flora urine cultures undergoing ureteroscopy.

Purpose of the Study:

• To determine the clinical significance of mixed flora in preoperative urine cultures.
• To compare postoperative infection rates in patients with mixed flora, negative, and positive urine cultures.
• To assess the effectiveness of preoperative antibiotics in patients with mixed flora urine cultures.

Main Methods:

• Retrospective cohort study of adult patients undergoing ureteroscopy with laser lithotripsy (January 2014 - June 2024).
• Patients categorized into mixed flora, negative, or positive preoperative urine culture groups.
• Comparison of 30-day postoperative urinary tract infection (UTI) rates using logistic regression.

Main Results:

• 5166 patients included: 2139 mixed flora, 1525 negative, 1502 positive cultures.
• Postoperative infection rates: 8% (mixed flora), 6% (negative), 16% (positive).
• Mixed flora and negative cultures showed similar infection risk; positive cultures significantly increased risk (OR=1.95). Preoperative antibiotics did not reduce infection in mixed flora cases.

Conclusions:

• Preoperative mixed flora urine cultures are not associated with increased postoperative infection risk after ureteroscopy.
• Current practice of routine antibiotic use for mixed flora may not be beneficial.
• Further research is needed to optimize antibiotic strategies for endourologic procedures.