Post-percutaneous Nephrolithotomy Urosepsis: Does Stone Culture Add Value?

Abstract

Introduction: Percutaneous Nephrolithotomy (PCNL) is the most commonly performed intrarenal surgery worldwide for the management of renal stones. Despite the administration of perioperative antibiotic prophylaxis, a significant number of patients develop Systemic Inflammatory Response Syndrome (SIRS), and several research articles have reported post-PCNL sepsis in 0.4-3% of cases. Despite having a sterile preoperative urine culture, the incidence of sepsis mentioned above could possibly be attributed to the presence of organisms in the stone. These organisms may enter the bloodstream during surgery and manifest as urosepsis. Aim: To determine whether the microbial spectrum of preoperative urine and postoperative stone culture can serve as predictors of urosepsis. Materials and Methods: A prospective observational study was conducted at the Department of Urology at Bharati Medical College and Hospital, Pune, Maharashtra, India involving all patients (sample size=167) undergoing PCNL between August 2019 and July 2021. The PCNL procedure was performed according to standard guidelines. To obtain a renal stone culture, authors followed the technique described by Nemoy NJ and Stamey TA. Postoperatively, patients were closely monitored for signs of systemic inflammatory response. Demographic and continuous variables were summarised using mean and standard deviation, while categorical variables (such as urine culture and stone culture, organisms isolated) were summarised using frequency and percentage. Statistical analysis was performed using unpaired t-test for quantitative variables and Chi-square test for qualitative variables, with a significance level set at 5%. Results: The mean age of the study participants was 39 years. Although the spectrum of organisms differed in many cases, E.coli (11.4% versus 12.6%) was more prevalent in stone cultures compared to Enterococcus (9% versus 7.2%). Staphylococcus saprophyticus (66.6%) was isolated from stone cultures, while E.coli (66.6%) was predominant in urine cultures. Sepsis/SIRS was effectively managed with antibiotic treatment based on stone culture (p=0.001) rather than urine culture (p=0.047). Conclusion: Routine stone culture not only helps in better prediction of potential sepsis but also guides the appropriate choice of antibiotics for sepsis management.