# The effect of negative, single and multi‐organism positive cultures on outcomes following PCNL

## TL;DR

This study shows that positive stone cultures after kidney stone surgery are linked to worse outcomes like infections and readmissions, especially when multiple organisms are involved.

## Contribution

The study identifies multi-organism stone cultures as a risk factor for stone recurrence and highlights the need for tailored antibiotic strategies.

## Key findings

- Positive stone cultures were found in 56% of patients, with 25% having multiple organisms.
- Positive cultures were independently linked to higher odds of readmission and stone recurrence.
- Multi-organism cultures were associated with more frequent stone recurrence within 6 months.

## Abstract

This study aims to explore risk factors related to positive single and multi‐organism stone cultures and their association with postoperative complications in patients undergoing percutaneous nephrolithotomy (PCNL).

A retrospective review was performed on 293 PCNL patients with stone cultures at a single academic institution between January 2017 and March 2023. Data collection encompassed demographics, comorbidities, operative details and postoperative outcomes. Chi‐square and ANOVA with Tukey B post hoc tests were employed. Multivariable logistic regression identified independent outcomes. Significance was set at p < 0.05.

Positive stone cultures were seen in 56% of patients and cultures with multiple organisms were seen in 25% of patients. Female sex (p = 0.007), preoperative nephrostomy tubes (p < 0.001) and longer surgical durations (p < 0.001) were more likely to have positive cultures. Significant associations were observed between positive cultures and postoperative fever (p = 0.007), readmissions (p = 0.020), stone recurrence (p = 0.002) and multidrug resistance (p = 0.016) with no difference between single‐ and multi‐organism culture groups. Positive cultures were independently associated with higher odds of readmission (OR = 4.31; p = 0.03) and stone recurrence (OR = 2.89; p = 0.005). Additionally, calcium phosphate and struvite stones were associated with positive cultures (p < 0.001).

Positive stone cultures (single or multi‐organism) predicted adverse postoperative outcomes including fever, readmission and recurrence. Patients with multi‐organism stone cultures were more likely to have stone recurrences within 6 months, suggesting the need for closer follow‐up and more comprehensive antibiotic therapy. These findings emphasize the role of stone culture status in guiding risk stratification and tailored prophylactic strategies, particularly in patients with multi‐organism stone cultures who have multidrug resistance.