BLOODSTREAM INFECTION BY BACILLUS CEREUS IN A COMMUNITY PATIENT: CASE REPORT OF AN UNUSUAL INFECTION

Bacillus cereus is a ubiquitous spore-forming environmental bacterium that produces toxins responsible for its pathogenicity in gastrointestinal and other infections. Systemic infections are associated with immunosuppression, neonates, drug use and intravascular catheters. Increasingly, potentially fatal extra-intestinal infections have been reported, but bacteremias due to this agent in community-dwelling elderly patients are rarely described. The objective of this study is to describe a case of bacteremia in a patient without known risk factors, of community origin. A 91-year-old woman with advanced dementia and dysphagia was admitted to a tertiary hospital with hypoactivity and poor oral intake for two days, without fever or respiratory or urinary symptoms. She was hospitalized for clinical investigation; initial laboratory tests showed leukocytosis (18,000 with 1% bands), elevated CRP and acute renal failure (Cr: 2.48). Chest CT was suggestive of bronchopneumonia, and cefepime was started due to a history of hospitalization for respiratory infection one month earlier. Within 24 hours of admission, she developed diarrhea without blood or mucus, which persisted. Testing for C. difficile toxins A and B was negative. She showed no clinical improvement and, after one week, developed fever and worsening mental status. Blood cultures were obtained due to suspected sepsis, and antibiotic therapy was escalated to meropenem. She had no invasive devices and no other localizing symptoms besides diarrhea. At 72 hours, Bacillus cereus was identified in two blood culture samples and a glycopeptide (teicoplanin) was initiated, with improvement of sepsis. Because it is widely present in soil, B. cereus is often considered a contaminant in sterile samples, but it can cause severe infections. Recognizing B. cereus as a systemic pathogen, even in the absence of classic risk factors, as in this case, is essential for appropriate therapeutic intervention.