An older man with Bifidobacterium breve bacteremia, a rare condition in adults: A case report.

Bifidobacterium breve is an anaerobic, gram-positive rod commonly found in the human intestinal microbiota. While rarely associated with bacteremia, most cases occur in neonates receiving B. breve-containing probiotics. Here, we report a rare case of B. breve bacteremia in an 80-year-old man presenting in cardiopulmonary arrest, despite not taking B. breve-containing probiotics. Blood cultures identified B. breve, and an 18-day course of antibiotics resolved the bacteremia. The rarity of adult cases may reflect age-related microbiota shifts and potential underdiagnosis due to the limited accuracy of rapid identification kits used in clinical practice.