Physical and Biological Hazards of the Workplace, 3rd Edition

Chapter 23MYCOBACTERIA

Gregg M. Stave*

MYCOBACTERIUM TUBERCULOSIS (M. tb.)

Common names for disease: Tuberculosis, consumption

Occupational setting

Tuberculosis (TB) exposure may occur in healthcare facilities, including hospitals, dental clinics and nursing homes, and in clinical or research laboratories processing tuberculosis cultures or infected specimens. Exposure may occur in funeral homes and is a significant risk in drug treatment centers, in correctional institutions, and in facilities for the homeless, alcoholics, or persons with AIDS. Animal caretakers can contract tuberculosis from primates even though the animal may not appear ill. Maintenance and construction workers may be exposed while manipulating ventilation systems for patient care isolation rooms or for biologic safety cabinets in which infectious samples are handled.

Exposure (route)

Tuberculosis is contracted after inhalational exposure via droplet nuclei that are 1–5 µm in size and thus remain airborne for long periods of time. TB is not contracted by skin contact with surfaces such as hospital room furniture, equipment, or walls. Infection by gastrointestinal exposure is not a significant risk.

Pathobiology

There are more than 30 members of the genus Mycobacterium, many of which are saprophytes that cause no human disease. Mycobacterium tuberculosis is the organism that causes tuberculosis. The surface lipids of mycobacteria cause them to be resistant to decolorization by acid alcohol during staining ...