Veille documentaire MTPH

Auteur     Caterina Zanetti
Auteur     Marta Peracchi
Auteur     Diego Zorzi
Auteur     Silvia Fiorio
Auteur     Loredana Fallico
Auteur     Giorgio Palù
Résumé     Interferon-γ release assays were recently introduced in health care worker (HCWs) screenings for tuberculosis surveillance. In longitudinal surveys, conversions and reversions are seen, yet whether these changes are unspecific or are an expression of new infections and microbial clearance remains unclear. In order to further elucidate these changes, we analyzed an outbreak of 15 transient conversions in 53 HCWs who operate in the same laboratory and handle specimens potentially containing Mycobacterium tuberculosis, that underwent screening by QuantiFERON-TB Gold In-Tube (QFT GIT®) between May 11-June 30, 2010: 15/46 (33%) negative HCWs showed a conversion, then reverted after 7-107 days. To validate these results, an evaluation of methodological procedures and test reliability, as well as an analysis of results obtained during the same period and processed by the same laboratory, were carried out. For this last purpose, QFT-GIT® results of 78 ward HCWs that in the same period underwent screening being employed in departments with at least 3 infectious tuberculosis patients per year or having cared an infectious patient without airborne precautions were analyzed: 6/63 (9%) negative HCWs attending at 3 different departments showed transient conversion (p=0.002; Odds Ratio 4.60, 95% Confidence Interval 1.62-13.04). A retrospective survey of in house biosafety practices lead to a single exposition factor within the laboratory. These data emphasize the hypothesis that transient conversions demonstrate a real tubercular infection and could be an important indicator for occupational biosafety concerns. They also confirm that subjects with recent conversion should be retested before offered chest radiography and chemotherapy.
Publication     Clinical and Vaccine Immunology: CVI
Date     Apr 18, 2012