Document Type

Conference Proceeding

Publication Date

5-1-2026

Abstract

Background Beta-lactam antibiotics are preferred for invasive methicillin-sensitive Staphylococcus aureus (MSSA) infections, especially those involving prosthetic material. Management is challenging in patients with severe beta-lactam hypersensitivity, as alternative agents may be less effective or poorly tolerated. Limited guidance exists on reassessing desensitization risk when second-line therapies become untenable. Purpose To present a case-based risk-benefit framework for evaluating beta-lactam desensitization in medically complex patients with life-threatening MSSA infections. Methods We retrospectively reviewed a patient with recurrent MSSA prosthetic graft infection and severe beta-lactam hypersensitivity. Clinical decision-making was analyzed using a structured risk–benefit framework incorporating infection severity, therapeutic superiority of beta-lactams, tolerance of alternative agents, allergy phenotype, and clinical trajectory. Antibiotic allergy history was contextualized with immediate multisystem reactions interpreted as high-risk Type I hypersensitivity. Multidisciplinary input informed management. Results A 37-year-old man with end-stage renal disease on hemodialysis and prior ascending aortic graft repair developed recurrent MSSA bacteremia complicated by mediastinal abscess and suspected graft infection. Due to severe immediate reactions to beta-lactams, he was treated with daptomycin and rifampin. His course was complicated by recurrent hospitalizations and intolerance to daptomycin requiring dose reduction, raising concern for inadequate treatment. As options narrowed, application of the framework demonstrated that the risk of ongoing infection outweighed the risk of allergic reaction, prompting consideration of ICU-based nafcillin desensitization using a 16-step protocol. Discussion and Conclusion This case demonstrates that desensitization decisions should be guided by dynamic clinical risk assessment rather than allergy history alone. Intolerance to second-line therapy may justify beta-lactam desensitization despite high predicted allergic risk.

Comments

American College of Physicians Michigan Chapter and Society of Hospital Medicine Michigan Chapter 2026 Resident and Medical Student Day, May 1, 2026, Troy, MI

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