Real-Time Therapeutic Drug Monitoring (TDM)-Based Pharmacokinetic/Pharmacodynamic (PK/PD) Optimization of Complex Antimicrobial Therapy in a Critically Ill Morbidly Obese Patient. Grand Round/A Case Study

The authors present the case of a critically ill morbidly obese patient (body mass index (BMI), 51.2 kg/m) who suffered from methicillin-resistant Staphylococcus epidermidis (MRSE), and Candida albicans bloodstream infections. Initial treatment with caspofungin and daptomycin was deemed inappropriate, as blood cultures remained positive for both isolates after 14 days. The clinical pharmacological consultant suggested adding fluconazole and ceftobiprole to the ongoing antimicrobial therapy, as well as starting a real-time TDM program of daptomycin, ceftobiprole, and fluconazole, aimed at optimizing plasma exposures. Punctual MIC knowledge on the clinical isolates allowed attainment of the desired pharmacodynamic efficacy targets. Within few days, the patient greatly improved, as blood cultures became negative, and the inflammatory markers decreased to near normal values. This is a proof-of-concept of the importance of a TDM-based multidisciplinary approach in the proper management of complex antimicrobial therapy in special populations.