Persistent Bacillus cereus Bacteremia in a Patient with Systemic Sclerosis-Associated Intestinal Pseudo-obstruction: A Case Report

Background Bacillus cereus is a spore-forming, Gram-positive rod often considered a blood culture contaminant but can cause persistent bacteremia, particularly in patients with intravascular catheters or impaired mucosal barriers. Optimal management without an identifiable source remains unclear. Case Presentation We describe a 62-year-old woman with diffuse systemic sclerosis (CREST spectrum, not on immunosuppressive therapy) complicated by interstitial lung disease, pulmonary arterial hypertension, and chronic intestinal pseudo-obstruction requiring total parenteral nutrition via a tunneled central venous catheter. She presented with rhabdomyolysis and dehydration and was found to have persistent Bacillus cereus bacteremia. Blood cultures remained positive for nearly two weeks despite catheter removal and susceptibility-guided antimicrobial therapy. Extensive evaluation, including transthoracic echocardiography, cardiac CT, PET-CT, and an indium-111-labeled white blood cell scan, revealed no endocarditis or any other source. Bacteremia cleared only after gentamicin was added to vancomycin. Despite recommendations to continue intravenous therapy, she completed treatment with oral clindamycin because of financial and personal constraints. Conclusion Bacteremia persisted for nearly two weeks despite catheter removal, arguing against a purely device-related source and suggesting occult gastrointestinal translocation driven by the mechanical and mucosal consequences of severe systemic sclerosis–associated gut dysmotility rather than pharmacologic immunosuppression. Clearance required combination antimicrobial therapy, highlighting the gut as a potential occult reservoir for bacteremia in patients with severe intestinal pseudo-obstruction, and suggesting that diffuse, nonspecific findings on functional imaging may serve as a diagnostic clue when no discrete source is identified.