A Rare Case of Disseminated Bacteroides fragilis Sternoclavicular Osteomyelitis Following Cardiopulmonary Resuscitation (CPR) in an Immunocompromised Patient: Is CPR the Missing Link?

Primary sternoclavicular osteomyelitis is uncommon and often misdiagnosed due to its nonspecific presentation, with anaerobic involvement, particularly by Bacteroides fragilis, being exceptionally rare and typically occurring in immunocompromised patients. We report the case of a 73-year-old man with multiple comorbidities, including diabetes mellitus, chronic kidney disease, ischaemic heart disease, and a chronic heel ulcer, who presented with fever and dyspnoea following a recent pulseless electrical activity arrest and successful cardiopulmonary resuscitation (CPR). Although initially managed for chronic calcaneal osteomyelitis, persistently elevated inflammatory markers and new anterior chest wall swelling prompted imaging that revealed a multiloculated abscess with sternoclavicular joint erosion, and blood cultures subsequently confirmed B. fragilis. Image-guided drainage and prolonged targeted antibiotic therapy resulted in both clinical and radiological improvement, allowing surgical intervention to be avoided given his high operative risk. This case underscores the importance of considering anaerobic pathogens in osteomyelitis among immunocompromised individuals and suggests a possible association between CPR-related microtrauma and subsequent sternoclavicular joint infection, highlighting the need for early multidisciplinary assessment and management.