Containment of active pulmonary tuberculosis in a long-term care/psychiatric center following exposure from a housekeeper

Abstract

BACKGROUND: Diagnosis of tuberculosis (TB) disease in an employee requires broad and aggressive contact investigation and employee education to identify exposures and prevent further spread. A housekeeping employee (source) was diagnosed with active pulmonary tuberculosis in June 2004. The source was potentially infectious from January to May 2004, prior to diagnosis and treatment. Risk of transmission was relatively high due to AFB smear-positive, cavitary disease. METHODS: An exposure was defined as sharing an enclosed airspace with the source for more than 10 minutes. Infection control personnel identified employees who had unprotected exposure to the source using time cards, which indicated areas where the source worked. Exposed employees were screened using purified protein derivative (PPD) 10-12 weeks after exposure; employees that were previously PPD positive completed questionnaires regarding signs and symptoms of TB. Screened employees also received training on TB detection and prevention and a TB fact sheet that was developed. An exposed employee with a PPD of 5mm or more was considered TB infected. TB infected employees had chest x-rays to rule out active disease and were offered treatment to prevent development of TB disease. RESULTS: Time card analysis indicated source assignment in the following areas: emergency room and outpatient clinic, six mental health inpatient units, four nursing home care units, geriatric long-term care unit, acute medical unit, research building, and police station. A total of 303 employees were exposed and were PPD skin tested. Two EMS employees and a nurse converted for a conversion rate of ∼1%. Their contacts with the source included riding in a car and singing in a chorus. These employees were treated with a 9-month course of isoniazid. Annual TB skin testing has not identified further cases. CONCLUSION: An employee with active TB can expose many medical center employees and patients to the infection prior to detection. Widespread contact investigation is effective in identifying exposed employees and preventing the spread of TB in a healthcare facility.