Infectious Complications After Laser Vaporization of Urinary Stones During Retrograde Intrarenal Surgery Are Not Associated with Spreading of Bacteria into Irrigation Fluid but with Previous Use of Fluoroquinolones

Disrupting Biofilms on Human Kidney Stones-A Path Toward Reducing Infectious Complications During Stone Surgery

Kidney stones are a common disorder associated with significant morbidity and often requires surgical intervention. Pathogenic bacteria are found in almost 40% of stones, where they form biofilms that are protected from systemic antibiotic treatments. Stone surgeries disperse biofilms resulting in up to 30% of patients developing postoperative urinary tract infections and 15% developing sepsis. This work is based on the hypothesis that chitosan, an antimicrobial polymer, can eradicate bacterial biofilms present in the stone and potentially serve as an adjunct to irrigation during stone surgery. First, fresh patient-derived kidney stone fragments (n = 56) are collected from stone surgeries. A total of 32% of stones are colonized, predominantly with Enterococcus faecalis, Escherichia coli, and Proteus mirabilis. A short, clinically relevant, chitosan treatment reduces the bacterial burden on colonized stones by over 90% in all specimens tested, regardless of stone composition and bacterial strain. To assess this approach toxicity, ex vivo human ureters and in vivo porcine bladders are exposed to topical chitosan irrigation. No toxic or pathological abnormalities other than urothelial exfoliation are noted. In conclusion, chitosan effectively disrupts kidney stone-associated bacterial biofilms with minimal urothelial toxicity and may provide an effective and safe approach to reducing postoperative complications.

Can We Identify Patients in Danger of Complications in Retrograde Intrarenal Surgery?-A Retrospective Risk Factors Analysis

Retrograde intrarenal surgery (RIRS) is an innovative and effective method of kidney stones treatment, as it had great influence on the development of endoscopy in urology. The increasing prevalence of urolithiasis together with the rapid development of endourology leads to a rise in the number of procedures related to the disease. Flexible ureteroscopy is constantly being improved, especially regarding the effectiveness and safety of the procedure. The purpose of this study is to evaluate intraoperative and early post-operative complications of RIRS in the treatment of kidney stones. A retrospective analysis of medical records was performed. A series was comprised of 207 consecutive operations performed from 2017 to 2020. Complications occurred in 19.3% (n = 40) of patients. Occurrence according to the Clavien-Dindo scale was: 11.1% for grade I, 5.8% for grade II and 2.4% for grade IV. Infectious complications included SIRS (5.3%, n = 11) and sepsis (2.4%, n = 5). Statistical analysis revealed a correlation between acute post-operative infections and positive midstream urine culture, history of chronic or recurrent urinary tract infections, and increased body mass index (BMI). Furthermore, a significant correlation was observed between pain requiring the use of opioids with BMI over 25. Consequently, history of urinary tract infections, positive pre-operative urine culture, and increased BMI are considered risk factors and require appropriate management.

Risk factors of febrile urinary tract infections following retrograde intrarenal surgery for renal stones

We aimed to evaluate the risk factors of febrile urinary tract infection (UTI) following retrograde intrarenal surgery (RIRS) for treating renal stones.We retrospectively reviewed the data of patients with 10 - 30 mm kidney stones who underwent RIRS from January 2014 to July 2017. Evaluation included age, gender, body mass index, stone size, stone location, and operative time. All surgeries were performed by a single surgeon and ureteral stenting was not done prior surgery. The risk factors of febrile UTI after RIRS were assessed by univariate and multivariate logistic regression analysis.A total of 150 patients were included in the present study, and 17 patients (11.3%) had febrile UTI after RIRS. Mean patient age was 56.64 ± 13.91 years, and both genders were evenly distributed. Mean stone size was 14.16 ± 5.89 mm. and mean operation time was 74.50 ± 42.56 minutes. According to univariate analysis, preoperative pyuria was associated with postoperative febrile UTI. Multivariate logistic regression analysis showed that preoperative pyuria was the only independent risk factor of infectious complications after RIRS (odds ratios 8.311, 95% confidence intervals 1.759 - 39.275, P = .008). Age, gender, body mass index, comorbidity, preoperative bacteriuria, presence of hydronephrosis, renal stone characteristics, and operative time were not associated with febrile UTI after RIRS.Preoperative pyuria was the only risk factor of infectious complications following RIRS. Therefore, careful management after RIRS is necessary especially when preoperative urinalysis shows pyuria.

External Validation of Two Predictive Models for Postoperative Fever After Retrograde Intrarenal Surgery in Pediatric Patients

Objective: The aim of this study is to validate the efficacy and reliability of two predictive models for postoperative fever after retrograde intrarenal surgery (RIRS) in pediatric patients Materials and Methods: A total of 124 children who were treated with RIRS between August 2014 and August 2020 in our center were included. All the predictors were obtained by preoperative routine examinations. Receiver operative curve (ROC) and area under curve (AUC) were showed to compare the predictive power of the two models. Results: One hundred twenty-four children included of 94 boys and 30 girls, with median ages of 2.1 (1.3, 7.0) years and median body mass index of 17.3 (15.6, 20.6) kg/m². The total points of the two nomograms were 81.0 (67.3, 90.3) and 45.5 (20.4, 94.0). Eventually, 21 children (16.9%) suffered from postoperative fever. With the exception of C-reactive protein values (25.0 mg/L vs 5.0 mg/L, p = 0.015), irrigation volumes (800 mL vs 500 mL, p = 0.01), and total points of the two predictive models (Nomogram 1: 88.0 vs 76.0, p < 0.001; Nomogram 2: 76.0 vs 39.0, p = 0.016), there was no statistical difference detected between the fever and nonfever groups. ROCs showed that Nomogram 1 presented with better predictive accuracy and efficacy with excellent AUC values of 0.805 in comparison with Nomogram 2 (0.805 vs 0.664, p = 0.025). Conclusion: We reported a sample of 124 children undergoing RIRS with a final stone-free rate of 87.1%. Twenty-one pediatric patients (16.9%) suffered from postoperative fever. Nomogram 1 presented with better predictive power for postoperative fever after RIRS in pediatric patients.

Feasibility and relevance of urine culture during stone fragmentation in patients undergoing percutaneous nephrolithotomy and retrograde intrarenal surgery: a prospective study

PURPOSE

We evaluated if, during lithotripsy, bacteria may be detected in the irrigation fluid of percutaneous nephrolithotomy (PCNL) and retrograde intrarenal surgery (RIRS). The concordance between urine culture from stone fragmentation (SFUC), bladder (BUC), renal pelvic (RPUC) and stone (SC) was analyzed. We also assessed the correlation between variables and cultures and their association with systemic inflammatory response syndrome (SIRS) and of a positive SC.

METHODS

We included 107 patients who underwent PCNL (n = 53) and RIRS (n = 54) from January 2017 to May 2018. Samples for RPUC were obtained by renal catheterization. Stone fragments and irrigation fluid sample were sent for culture.

RESULTS

SFUC was positive in 17 (15.9%), BUC in 22 (20.6%), RPUC in 26 (24.3%) and SC in 30 patients (28%). The concordance between SFUC and SC was the highest among all cultures: 94.1%. SFUC and SC grew identical microorganisms in 15/17 (88.2%) patients. Out of 17 (15.9%) patients with SIRS, 8 (7.5%) had sepsis. SFUC had the highest PPV and specificity to detect positive SC and SIRS. Previous urinary tract infection, a preoperative nephrostomy, stone diameter and composition, staghorn calculi, PCNL, positive BUC, RPUC and SFUC were predictors of infected stone. Variables that indicate complex stones, complex PCNL and an infection of the upper tract were associated with SIRS.

CONCLUSION

SFUC is technically feasible, easy to retrieve and to analyze. The spectrum of SFUC potential application in clinical practice is when is not possible to perform a SC, e.g. complete dusting or during micro-PCNL.

Bacterial spectrum and antibiotic resistance of urinary tract infections in patients treated for upper urinary tract calculi: a multicenter analysis

The purpose of this study is to collect information on the bacterial resistance to antibiotics of bacteria isolated from urine cultures of patients treated for upper urinary tract calculi. Data of patients with urinary tract infection and urolithiasis were retrospectively reviewed to collect information on age, gender, stone size, location, hydronephrosis, procedure of stone removal and antibiotic treatment, identification and susceptibility of pathogens, symptoms, and infectious complications. A total of 912 patients from 11 centers in 7 countries (Bulgaria, Greece, Italy, North Macedonia, Spain, and Turkey) were studied. Mean age was 54 ± 16 years and M/F ratio 322/590. Out of 946 microbial isolates, the most common were E. coli, Gram-positive, KES group (Klebsiella, Enterobacter, Serratia), Proteus spp., and P. aeruginosa. Carbapenems, piperacillin/tazobactam and amikacin showed low resistance rates to E. coli (2.5%, 7%, and 3.6%) and Proteus spp. (7.7%, 16%, and 7.4%), but higher rates were observed with Klebsiella spp., P. aeruginosa, and Gram-positive. Fosfomycin had resistance rates less than 10% to E. coli, 23% to KES group, and 19% to Gram-positive. Amoxicillin/clavulanate, cephalosporins, quinolones, and TMP/SMX showed high resistance rates to most bacterial strains. High rates of antibiotic resistance were observed in patients candidate to stone treatment from South-Eastern Europe. The empirical use of antibiotics with low resistance rates should be reserved to the most serious cases to avoid the increase of multidrug resistant bacteria. Basing on our results, carbapenems, piperacillin/tazobactam, and amikacin may be a possible option for empiric treatment of urinary stone patients showing systemic symptoms.