A Case of Pyogenic Spondylitis and Psoas Abscess Suspected to Result from <i>Salmonella Johannesburg</i> Bacteremia: Involvement of an Antimicrobial Stewardship Team Pharmacist in Diagnosis and Treatment

Pharmacists on an antimicrobial stewardship team (AST) play a crucial role in improving outcomes for patients with serious infectious diseases. However, although AST pharmacists are often involved in the selection of treatment or dosage adjustments, few studies have investigated AST-led interventions for the diagnosis and treatment of severe infections. Herein, we present a case in which an AST pharmacist helped diagnose and treat pyogenic spondylitis and an iliopsoas abscess suspected to be caused by Salmonella. After admission, a primary care physician treated the patient with meropenem for severe sepsis. On day 4, Salmonella spp. was identified in two sets of blood cultures. After confirming antimicrobial susceptibility, an AST pharmacist recommended an additional intravenous dose of 500 mg of levofloxacin once daily. This 2-week treatment regimen for Salmonella bacteremia was terminated because of improvement in the patient’s condition. However, during the posttreatment follow-up, the AST pharmacist observed a gradual onset of pain in the patient’s back, hip joints, and groin. Consequently, the AST pharmacist recommended blood culture and whole-body assessment using computed tomography and magnetic resonance imaging. Although the blood cultures were negative, diagnostic imaging confirmed psoas abscess and pyogenic spondylitis. The AST pharmacist recommended a 6-week treatment regimen of 2.0 g ceftriaxone twice daily combined with 500 mg levofloxacin once daily. Salmonella was later identified as Salmonella Johannesburg (O1, 40, n, x) via biochemical testing and serotyping using commercial antisera. This case highlights the importance of continuous patient monitoring and the vital role of AST pharmacists in guiding comprehensive treatment.