title: Air filtration systems and restrictive access conditions improve indoor air quality in clinical units: Penicillium as a general indicator of hospital indoor fungal levels.
abstract: BACKGROUND
  High-efficiency particulate air (HEPA) filters do not completely prevent nosocomial fungal infections. The first aim of this study was to evaluate the impact of different filters and access conditions upon airborne fungi in hospital facilities. Additionally, this study identified fungal indicators of indoor air concentrations.
  
  
  METHODS
  Eighteen rooms and wards equipped with different air filter systems, and access conditions were sampled weekly, during 16 weeks. Tap water samples were simultaneously collected.
  
  
  RESULTS
  The overall mean concentration of atmospheric fungi for all wards was 100 colony forming units/m(3). We found a direct proportionality between the levels of the different fungi in the studied atmospheres. Wards with HEPA filters at positive air flow yielded lower fungal levels. Also, the existence of an anteroom and the use of protective clothes were associated to the lowest fungal levels. Principal component analysis showed that penicillia afforded the best separation between wards' air fungal levels. Fungal strains were rarely recovered from tap water samples.
  
  
  CONCLUSIONS
  In addition to air filtration systems, some access conditions to hospital units, like presence of anteroom and use of protective clothes, may prevent high fungal air load. Penicillia can be used as a general indicator of indoor air fungal levels at Hospital S. João.
authors.affiliation: Department of Microbiology, Faculty of Medicine, University of Porto, Porto, Portugal. ricjparaujo@yahoo.com
authors.forename: Ricardo
authors.initials: R
authors.lastname: Araujo
authors.forename: João Paulo
authors.initials: JP
authors.lastname: Cabral
authors.forename: Acácio Gonçalves
authors.initials: AG
authors.lastname: Rodrigues
mesh_terms: D000391:Air Microbiology; D016902:Air Pollution, Indoor / Q000032:analysis*; D015169:Colony Count, Microbial; D005374:Filtration; D005658:Fungi / Q000145:classification / Q000302:isolation & purification*; D006761:Hospitals; D017053:Infection Control / Q000379:methods; D011481:Protective Clothing; D014871:Water Microbiology