title: Immunosurveillance for Mycobacterium tuberculosis of health care personnel in a third level care hospital.
abstract: BACKGROUND
  Health care workers are at risk for Mycobacterium tuberculosis (MTB) infection.
  
  
  OBJECTIVE
  To perform an occupational health survey among 621 employees of a 800-bed third level care hospital covered by MTB surveillance.
  
  
  METHODS
  Statistical analysis was applied to results from tuberculin skin test (TST), QuantiFERON - TB Gold in tube assay (QFT), PPD-ELISA for serum antibodies, and occupational or vaccine data.
  
  
  RESULTS
  29.1% of subjects were TST positive, 18.5% were QFT positive. In 23% of subjects no correlation between these tests was found, presumably linked to BCG-vaccination, since TST positivity was 4 times higher among vaccinated subjects, whereas both tests correlated well in unvaccinated subjects. QFT values above 2 IU/ml were significantly associated with positive TST and age over 40 years. Working in MTB risk level 4 was significantly associated with QFT, TST and PPD-antibody levels, suggesting booster effects by repeated exposure. No clear correlation was observed with medical specializations but significantly higher QFTpositivity was found in subjects not assigned to the classical medical professions and originating from MTB high risk areas.
  
  
  CONCLUSIONS
  These results shift the focus on maintenance personnel, who mostly worked in MTB risk level 2 areas. The less positive QFT results in vaccinated subjects highlight QFT's advantage as a screening tool and argue for a protective effect of the BCG-vaccine, although percentages of vaccinated persons varied largely between different medical professions. Interestingly, the percentage of QFT positive persons was lower among subjects reporting MTB exposure than those who were not aware of exposure events.
authors.affiliation: Laboratorio di Microbiologia e Virologia, Azienda Sanitaria dell'Alto Adige, Bolzano, Italia. clara.larcher@asbz.it
authors.forename: Clara
authors.initials: C
authors.lastname: Larcher
authors.forename: Eliana
authors.initials: E
authors.lastname: Frizzera
authors.forename: P
authors.initials: P
authors.lastname: Pretto
authors.forename: Monika
authors.initials: M
authors.lastname: Lang
authors.forename: Nora
authors.initials: N
authors.lastname: Sonnleitner
authors.forename: H P
authors.initials: HP
authors.lastname: Huemer
mesh_terms: D000328:Adult; D000942:Antigens, Bacterial / Q000276:immunology; D001500:BCG Vaccine / Q000008:administration & dosage; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006282:Health Personnel; D006785:Hospitals, University; D006801:Humans; D059425:Interferon-gamma Release Tests / Q000706:statistics & numerical data*; D007558:Italy / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D015166:Monitoring, Immunologic / Q000379:methods; D009169:Mycobacterium tuberculosis / Q000276:immunology; D011933:Reagent Kits, Diagnostic; D014374:Tuberculin Test / Q000706:statistics & numerical data*; D014397:Tuberculosis, Pulmonary / Q000175:diagnosis* / Q000517:prevention & control*
chemical_list: D000942:Antigens, Bacterial; D001500:BCG Vaccine; D011933:Reagent Kits, Diagnostic