The effect of negative, single and multi-organism positive cultures on outcomes following PCNL.

OBJECTIVE

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).

SUBJECTS/PATIENTS AND

METHODS

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.

RESULTS

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).

CONCLUSION

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.