Which organism is commonly recovered from blood cultures in systemic infections and is associated with laboratory-acquired risk?

• A. Acinetobacter baumannii-calcoaceticus complex
• B. Brucella canis
• C. Chlamydia trachomatis
• D. Yersinia enterocolitica

Answer: (B)

Brucella species are classic systemic pathogens that frequently appear in blood cultures during bacteremia, reflecting infection that has spread beyond a localized site. What makes this group especially notable in the lab setting is their high infectivity by the inhalation route, which creates a real risk for laboratory-acquired infections during routine culture handling and processing. Brucella canis, a canine-associated Brucella, exemplifies this risk because it can cause human brucellosis and has long been recognized as a potential source of lab-acquired infection, necessitating stringent biosafety precautions. The other organisms listed do not have the same combination of common blood-culture–positive systemic infection and well-documented laboratory containment risk, so they don’t fit as clearly.