Therapeutic Drug Monitoring-Guided Linezolid Therapy for the Treatment of Multiple Staphylococcal Brain Abscesses in a 3-Month-Old Infant

Abstract

Brain abscesses are invasive infections of the central nervous system with a high level of treatment complexity especially in pediatric patients. Here, we describe a 3-month-old infant with multiple brain abscesses caused by methicillin-susceptible Staphylococcus aureus (MSSA). The patient was initially treated with empirical antibiotics (ceftriaxone, metronidazole, vancomycin). Upon MSSA identification, therapy was optimized by switching vancomycin to linezolid to improve tissue penetration. Therapeutic drug monitoring (TDM) was performed to check linezolid levels in the plasma and pus of the abscess, confirming drug penetration into brain tissue. A two-stage surgical drainage approach, consisting of repeated pus aspiration through an intracystic catheter, was then performed to achieve a significant reduction in abscess size. After nine weeks of antibiotic therapy, the patient was discharged in good clinical condition. This case highlights the role of linezolid for the treatment of complicated CNS infections and the importance of a multidisciplinary approach, combining TDM-based antibiotic therapy with timely and eventually repeated surgery, in order to effectively treat brain abscesses.

Keywords: brain abscess; linezolid; methicillin-sensitive Staphylococcus aureus (MSSA); multidisciplinary approach; therapeutic drug monitoring (TDM).

Figure 1

(a) The brain MRI scan at the admission showing the presence of multiple brain abscesses in the right hemisphere, the largest in the frontal (4 × 3.7 cm) and parietal (5.5 × 7.3 cm) lobes; (b) brain MRI performed after 8 weeks of intravenous antibiotic therapy and two surgical drainages revealing significant reduction in the lesions and a gliotic malacic evolution of parenchyma.

Figure 2

Linezolid concentrations in both plasma (light blue) and intracystic pus (dark blue) samples were measured immediately before (C_min) and 30 min after a 1 h intravenous infusion (C_max), ten days after initiating linezolid therapy. Dashed black lines indicate the desired concentration range for linezolid TDM.