B48-01 Cefepime-induced Neutropenic Fever in a Patient With Chronic MRSA Wound Infection: A Case Report

Introduction Cefepime is a fourth-generation cephalosporin commonly used to treat serious gram-negative infections. While generally well tolerated, rare adverse effects such as neutropenia and drug-induced fever can complicate prolonged therapy. Literature to date has documented approximately 15-20 confirmed cases of cefepime-induced neutropenia, with several complicated by febrile episodes. The mechanism is believed to involve either direct bone marrow suppression or immune-mediated destruction of neutrophils. Case Presentation A 39-year-old man with a history of a right knee burn from a space heater in December 2024, complicated by chronic wound infection, who presented for worsening drainage and pain. He had previously been treated for MSSA osteomyelitis and underwent multiple surgical interventions, including debridement and flap closure. Previous imaging raised concern for osteomyelitis, prompting initiation of intravenous daptomycin and cefepime. The patient subsequently underwent irrigation and debridement, with cultures yielding MRSA; his antimicrobial regimen was continued. On presentation, vitals were stable. Labs were remarkable for iron deficiency anemia. His hospital course was complicated by the development of new neutropenia (WBC 1.66 × 109/L) and high-grade fevers approximately 25 days into cefepime therapy. Broad infectious and surgical site evaluations were unrevealing. Given the timing and absence of another clear source, cefepime was suspected as the causative agent and discontinued. Within 48 hours, the patient’s fever and neutropenia resolved. He was transitioned to oral trimethoprim-sulfamethoxazole and continued daptomycin, with no recurrence of symptoms. He was subsequently discharged to a long-term acute care hospital for rehabilitation and continued intravenous antibiotics. Discussion Cefepime-induced neutropenic fever is a rare but recognized adverse drug reaction, often occurring after prolonged use. Reported incidence varies but has been estimated at approximately 1-2% in patients receiving prolonged therapy, with most cases occurring between 16 to 30 days of continuous therapy. The mechanism is thought to be immune-mediated or direct marrow suppression. While exact incidence is unknown, recent studies report clusters of cases in OPAT populations, suggesting the condition may be underdiagnosed. In this case, the association between cefepime initiation and onset of fever and neutropenia, as well as rapid resolution after discontinuation, supports a diagnosis of cefepime-induced neutropenic fever. This case underscores the importance of maintaining a broad differential in febrile neutropenia, particularly in patients receiving multiple antibiotics and undergoing extensive surgical procedures. Discontinuation of the offending agent can lead to swift recovery and prevent unnecessary interventions. Clinicians should maintain a high index of suspicion, especially in patients with complex infections and prolonged hospitalizations. This abstract is funded by: None