Healthcare-associated Exposure to Mycobacterium tuberculosis (MBT)
MBT is transmitted from person-to-person primarily by inhalation of droplets and droplet nuclei generated by talking, coughing, or sneezing. Health care personnel with a documented history of a prior positive TB test should receive an individual TB risk assessment and TB symptom screen upon hire (i.e., pre-placement). Otherwise, HCP should undergo baseline TB screening, including a symptom evaluation and testing (tuberculin skin test [TST] or , interferon-gamma release assay [IGRA]) at the beginning of employment.15,16 A positive TST or IGRA indicates prior exposure to MBT and the provider should be evaluated for the presence of tuberculosis (TB) disease or latent TB infection (LTBI).
HCP with a negative baseline TST or IGRA who experience an unprotected occupational exposure, are susceptible to infection. As soon as possible after exposure to a patient with TB disease, the provider should undergo a TST or IGRA test. If the result is negative, the test should be repeated at 8-10 weeks after the last exposure.
Immunocompetent providers with LTBI are asymptomatic and not infectious but have a 10% life-time risk of developing active TB. Treatment for LTBI is strongly encouraged for all HCP with LTBI. Shorter treatment regimens, including once-weekly isoniazid and rifapentine for 3 months and daily rifampin for 4 months, should be used as they are more likely to be completed when compared to the traditional regimens of 6 or 9 months of isoniazid.16