Mycobacterium tuberculosis is spread through infectious droplet nuclei. When a person infected with pulmonary tuberculosis coughs, sneezes, shouts, or sings, the infectious particles can be expelled into the air. The risk of infection is related to both the concentration of infectious droplet nuclei and the duration of exposure.
Clinical laboratory workers can be at an increased risk of exposure when infectious aerosols or droplets are generated from procedures such as:
- Setting up cultures or inoculating media
- Manipulating specimens and cultures
- Centrifugation
- Harvesting tissues
- Manipulating needles, syringes, and sharps
- Making smears
- Aspirating and transferring body fluids
- Preparation of frozen sections
- Performance of autopsies on infected patients
