抗菌薬適正使用支援チームの薬剤師による継続的な治療支援が奏功した脳膿瘍の1例

抄録

Pharmacists in antimicrobial stewardship teams play a pivotal role in optimizing antimicrobial selection and dosing for patients with severe infections. Although AST interventions have been associated with improved antimicrobial use and reduced antimicrobial resistance, evidence evaluating the impact of pharmacist-driven interventions throughout the diagnostic and therapeutic course of severe infections remains limited. We report the case of a patient with a severe brain abscess in whom continuous intervention by an AST pharmacist contributed to favorable clinical outcomes through the optimization of specimen collection, and antimicrobial therapy based on pharmacokinetic/pharmacodynamic principles. Empirical therapy with meropenem (6 g/day) and vancomycin, under therapeutic drug monitoring, was initiated on admission. Surgical drainage of the brain abscess was performed on hospital day 8. The AST pharmacist recommended the intraoperative collection of purulent material using anaerobic transport media, enabling anaerobic culture. Gram staining revealed gram-positive cocci (4+), gram-positive rods (3+), and gram-negative rods (1+). The gram-positive cocci were subsequently identified as Streptococcus constellatus. Based on the Gram staining findings suggestive of a concomitant anaerobic infection, therapy with ampicillin and metronidazole was proposed. Given the anticipated prolonged duration of therapy, the potential risk of metronidazole-associated central nervous system toxicity was shared with the medical team, and careful neurological monitoring was implemented. Overall antimicrobial therapy consisted of meropenem and vancomycin for 2 weeks, followed by ampicillin and metronidazole for 8 weeks, and was completed without adverse events. This case demonstrates the clinical value of a continuous pharmacist-driven AST intervention for the management of severe infections.