Which of the following is the most common agent reported in laboratory-acquired infections?

• A. Salmonella
• B. Brucella
• C. Neisseria
• D. Coxiella

Answer: (B)

Brucella is extremely infectious by the inhalation route, so even tiny aerosols generated during routine culture and specimen handling in the lab can cause illness. In many laboratory settings, work involves animal and clinical samples that may harbor Brucella, and aerosol-generating steps like vortexing, centrifuging, or opening sealed containers can expose staff. This combination—a very low infectious dose and a high likelihood of aerosol exposure during common lab tasks—has made Brucella the most frequently reported agent in laboratory-acquired infections. Other organisms listed can cause lab infections, but they typically require larger doses, different exposure scenarios, or are encountered less often in standard culture workflows, so they don’t show up as commonly in surveillance data as Brucella.