A recent study published in the World Journal of Urology found that the presence of contaminants in pre-operative urine cultures (preop-UC) does not predict the occurrence of post-operative urinary tract infections (postop-UTI) in patients undergoing ureteroscopy with laser lithotripsy. This finding could have considerable implications for preoperative care and antibiotic use in patients who are undergoing this common procedure for the treatment of kidney stones.

The study was conducted over a two-year period from January 2019 to December 2021 and focused on individuals with unilateral kidney stones smaller than 2 cm. This retrospective chart review of patients who had undergone ureteroscopy with laser lithotripsy ensured that a preop-UC was obtained within three months prior to the surgery. The study determined whether contaminants identified in these cultures had any bearing on the risk of developing UTIs following the procedure.
The patients included in the analysis were the individuals whose preop-UCs were negative, contaminated or showed polymicrobial growth, with the individuals showing positive growth for a specific organism being excluded from the study. The definition of a postop-UTI was strict that required both the presence of urinary symptoms and a positive urine culture within 30 days after the surgery.
Out of the 201 patients meeting the criteria for inclusion in the study, 153 patients had negative preop-UCs while 48 patients showed signs of contamination. The analysis revealed that factors such as female gender and a higher body mass index (BMI) were significantly associated with contaminated urine samples. However, the postop-UTI occurrence were nearly identical between patients with negative and contaminated preop-UCs, at 3.2% and 4.2% respectively that indicated no significant difference.
Through the use of multivariable logistic regression models, the outcomes concluded that the presence of contaminants in preop-UCs did not serve as a predictor for postop-UTIs. Overall, the findings of the study suggest that contaminants in preop-UCs should be considered as negative in terms of risk stratification for postop-UTIs which proposes a shift in the current approach towards the management of these patients. The study underscores the need for tailored antibiotic stewardship and highlights the importance of accurate risk assessment in patients who were undergoing ureteroscopy for stone disease.
Reference:
Ito, W., Choi, N., Letner, G., Genz, N., Prokop, D., Valadon, C., Sardiu, M. E., Smith, H., Whiles, B. B., & Molina, W. R. (2024). Preoperative urine culture with contaminants is not associated with increased risk for urinary tract infection after ureteroscopic stone treatment. In World Journal of Urology (Vol. 42, Issue 1). Springer Science and Business Media LLC. https://doi.org/10.1007/s00345-024-04793-w