title: A multicenter evaluation of tuberculin skin test positivity and conversion among health care workers in Brazilian hospitals.
abstract: METHODS
  Four general Brazilian hospitals.
  
  
  OBJECTIVE
  To assess the occupational risk of Mycobacterium tuberculosis (TB) in participating hospitals.
  
  
  METHODS
  In phase one of this longitudinal study, a cross-sectional survey documented baseline tuberculin skin test (TST) positivity rates. In phase two, TST conversion rates were evaluated in participants with an initial negative two-step TST. TST conversion data were analyzed to determine risk factors for TB infection using an increase of > or = 10 mm compared to baseline TST.
  
  
  RESULTS
  The initial TST positivity rate was 63.1%; the follow-up TST conversion rate was 10.7 per 1000 person-months (p-m). Hospital of employment, recent bacille Calmette-Guerin (BCG) vaccination, nosocomial TB exposure, and employment as a nurse were independent risk factors for TST conversion. Hospitals without TB infection control measures had higher conversion rates than those with control measures (16.0 vs. 7.8/ 1000 p-m, P < 0.001).
  
  
  CONCLUSIONS
  This study indicates an important occupational risk of infection in health care settings with a high TB incidence. Longitudinal TST studies are a valuable tool to assess the occupational risk of TB, even in BCG-vaccinated populations, and should be used to direct limited resources for infection control.
authors.affiliation: Division of Healthcare Quality Promotion, National Center for Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, USA. vroth@ottawahospital.on.ca
authors.forename: V R
authors.initials: VR
authors.lastname: Roth
authors.forename: D O
authors.initials: DO
authors.lastname: Garrett
authors.forename: K F
authors.initials: KF
authors.lastname: Laserson
authors.forename: C E
authors.initials: CE
authors.lastname: Starling
authors.forename: A L
authors.initials: AL
authors.lastname: Kritski
authors.forename: E A S
authors.initials: EA
authors.lastname: Medeiros
authors.forename: N
authors.initials: N
authors.lastname: Binkin
authors.forename: W R
authors.initials: WR
authors.lastname: Jarvis
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001500:BCG Vaccine; D001938:Brazil; D005260:Female; D006769:Hospitals, General; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D009784:Occupational Diseases / Q000453:epidemiology* / Q000209:etiology; D016273:Occupational Exposure / Q000009:adverse effects*; D010564:Personnel, Hospital; D012307:Risk Factors; D016036:Seroepidemiologic Studies; D014374:Tuberculin Test; D014376:Tuberculosis / Q000453:epidemiology* / Q000209:etiology / Q000517:prevention & control
chemical_list: D001500:BCG Vaccine