Which infection requires airborne isolation precautions?

• A. Active pulmonary tuberculosis.
• B. Influenza.
• C. Staphylococcus aureus pneumonia.
• D. Atypical pneumonia.

Answer: (A)

Airborne infections require precautions designed to protect against tiny aerosolized particles that can linger in the air and travel beyond immediate proximity. The classic example is active pulmonary tuberculosis. Tuberculosis is spread when someone with an infectious cough releases droplet nuclei into the air, and these small particles can be inhaled by others, sometimes after being carried by air currents for long distances. Because of this, airborne isolation is necessary, which includes placing the patient in a negative-pressure room and ensuring health-care workers and visitors wear an appropriate respirator, typically an N95, during contact with the patient. The patient should wear a mask if they must leave the room to minimize spread.

The other infections listed are not primarily transmitted through airborne routes. Influenza spreads mainly by larger respiratory droplets and contact with contaminated surfaces, not typically by fine airborne particles in routine care. Staphylococcus aureus pneumonia and atypical pneumonias are generally managed with droplet or contact precautions unless aerosol-generating procedures are involved, which would change the precaution needs. Hence, active pulmonary tuberculosis is the infection that requires airborne isolation precautions.