Pharmacokinetic of ceftazidime-avibactam in a critically ill patient under high-volume continuous venovenous haemodiafiltration: A first paediatric case report.

Ceftazidime-avibactam is a novel cephalosporin/B-lactamase inhibitor developed in the context of increasing resistance. This case reports the pharmacokinetics of ceftazidime-avibactam in a critically ill child under continuous renal replacement (CRRT) therapy for fluid overload. The patient was a 6-month-old female with sepsis due to bloodstream infection to Stenotrophomonas maltophilia following stem cell transplantation for severe combined immunodeficiency. CRRT was started on Day 2. Concentrations have been monitored using liquid chromatography-tandem mass spectrometry. Treatment was given every 8 h with a 2 h infusion of 30-7,5 mg/kg and did not reach pharmacokinetic/pharmacodynamic targets. Total clearance was respectively 1.7 and 3.02 L/h, with CRRT clearance respectively 28.8%-60% for ceftazidime and 14%-33% for avibactam. Those clearances are higher than reported in adult literature leading to a risk of treatment failure and emerging resistance. This supports the benefit of monitoring antimicrobial therapy under CRRT and the necessity to assess higher dosing or continuous infusion of ceftazidime-avibactam.