Serum vancomycin levels predict the short-term adverse outcomes of peritoneal dialysis-associated peritonitis

Vancomycin Dosing Strategy for the Treatment of Peritonitis in a Child on Automated Peritoneal Dialysis: A First Pediatric Case Report

BACKGROUND

Bacterial peritonitis is a common complication of peritoneal dialysis. In the absence of systemic signs of infection, adult guidelines recommend treatment with intraperitoneal vancomycin either as empiric coverage of gram-positive organisms or as targeted therapy. However, there is no guidance on how to administer vancomycin in children on automated peritoneal dialysis.

CASE REPORT

We report vancomycin pharmacokinetics upon intraperitoneal administration for the treatment of a Staphylococcus hominis peritonitis in an 11-year-old patient on automated nocturnal intermittent peritoneal dialysis. While the patient was hospitalized, vancomycin was administered intraperitoneally as a continuous treatment. After hospital discharge, the nocturnal peritoneal dialysis was resumed. In the absence of treatment guidelines, intraperitoneal vancomycin was initially administered empirically only during the nocturnal dialysis exchanges which led to repetitive subtherapeutic vancomycin plasma concentrations and the persistence of S. hominis in dialysate cultures. Based on studies in adults, the dosing strategy was subsequently modified to administer vancomycin at a dosage of 15 mg kg-1 in the dialysate with a 6-h dwell period prior to the nocturnal dialysis thereby allowing to reach optimal peak concentrations. The dosing interval was subsequently individualized using therapeutic drug monitoring to ensure residual vancomycin concentrations > 10 mg L-1 thereby leading to clinical and microbiological recovery.

CONCLUSIONS

This case presents a dosing strategy based on a comprehensive review of the literature and highlights that a sufficient dwell period is critical when treating pediatric patients on automated peritoneal dialysis in order to allow vancomycin distribution and equilibration between the dialysate and the plasma.

The Association Between Serum Vancomycin Level and Clinical Outcome in Patients With Peritoneal Dialysis Associated Peritonitis

Introduction

Intraperitoneal (IP) vancomycin is often first-line empiric therapy and then maintenance therapy for peritoneal dialysis (PD) peritonitis. However, how vancomycin serum levels correlate with clinical outcomes remains unclear.

Methods

We conducted a retrospective single-center adult cohort study of 98 patients with PD peritonitis treated with IP vancomycin between January 2016 and May 2022. The association between nadir vancomycin level and cure was evaluated in a logistic regression model, first unadjusted and then adjusted for age, sex, weight, glomerular filtration rate (GFR), and total number of days on PD. Vancomycin was assessed both as a continuous exposure (per 1 mg/l increase) and as a categorical exposure (<15 mg/l vs. ≥15 mg/l). A receiver operating characteristic curve (ROC) was created to explore nadir vancomycin level thresholds in an attempt to identify an optimal target level during treatment.

Results

Of the patients, 81% achieved cure, and patients with nadir vancomycin level ≥15 mg/l were 7.5 times more likely to experience cure compared to those with a nadir level <15 mg/l (odds ratio [OR] 7.58, 95% confidence interval [CI] 1.71-33.57, P = 0.008). Weight, GFR, days on PD, sex, and age were not independently associated with outcome. The vancomycin level with the greatest discriminatory capacity for cure on the ROC analysis was 14.4 mg/l.

Conclusion

Increasing IP vancomycin serum levels are associated with increased odds of cure; and maintaining vancomycin serum levels above 14-15 mg/l throughout the course of PD peritonitis treatment is likely to improve clinical outcomes.