Tuberculosis contacts, concerns, and controls: what matters for healthcare workers? Society of Hospital Epidemiologists of America

摘要

Healthcare workers (HCWs) are at risk of becoming infected with Mycobacterium tuberculosis through occupational exposure. The magnitude of the risk varies according to the setting, occupational group, prevalence of tuberculosis in the community, patient population served, immunocompetency of the worker, and effectiveness of infection control programs. HCWs are tested periodically for M. tuberculosis infection, and the frequency of testing is determined by the likelihood of exposure to patients with infectious tuberculosis. The QuantiFERON-TB Gold test (QFT-G) is a new tool whose usefulness will greatly benefit from analysis of program-based postmarketing surveillance data.In 2005, the Centers for Disease Control and Prevention (CDC) published 2 guidelines that highlight the importance of surveillance for tuberculosis infection among HCWs and address the complexities of setting up infection control practices to perform such surveillance. Until recently, the only practical method for detecting asymptomatic infection due to M. tuberculosis was the tuberculin skin test (TST). The QFT-G is an ex vivo assay that measures the release of interferon {IFN-?) in whole blood in response to stimulation by antigens that are more specific to M. tuberculosis than is tuberculin purified protein derivative (PPD).6 Because the QFT-G is an ex vivo assay, this test does not cause boosting when it is repeated. In healthcare settings where serial testing is conducted, initial 2-step testing with QFT-G is not recommended. For TST-based serial testing for HCWs, initial 2-step testing is necessary to establish a baseline infection status, to avoid interpreting boosting as a new infection, and to prevent subsequent unnecessary treatment for latent tuberculosis infection (LTBI).