Bacillus cereus bacteremia with central nervous system involvement: A neuropathological study.

Bacillus cereus is a widely-distributed, gram-positive or variable, rod-shaped bacterium frequently considered a contaminant in clinical specimens. It is recognized as a potential pathogen inducing self-limiting emetic or diarrheal food poisoning or localized infection in immunocompetent patients. True B. cereus bacteremia is uncommon and mainly observed in fragile patients, notably in immunocompromised individuals. We report clinical, radiological, and pathological findings of a 64-year-old patient with a history of acute myeloid leukemia who initially presented a fever while neutropenic after the induction of a second cycle of chemotherapy. He developed B. cereus bacteremia with invasive infection and a fatal outcome. The clinical and radiological data of this case are compared to a previously-published series of 21 patients from our institution with B. cereus bacteremia. This study highlights the clinical challenge to diagnose B. cereus and the importance of the delay between the detection of B. cereus and the initiation of an effective targeted antibiotic therapy. This case presented an aggressive evolution with multiple necrotic and hemorrhagic foci in the brain. Upon histological examination, B. cereus virulence was notably reflected by the dissection of blood vessel walls by the bacilli and luminal occlusion, a pattern that has not been yet reported. .