title: Risk of bioaerosol contamination with Aspergillus species before and after cleaning in rooms filtered with high-efficiency particulate air filters that house patients with hematologic malignancy.
abstract: OBJECTIVE
  To examine the impact of cleaning and directional airflow on environmental contamination with Aspergillus species in hospital rooms filtered with high-efficiency particulate air (HEPA) filters that house patients with hematologic malignancy.
  
  
  METHODS
  Detailed environmental assessment.
  
  
  METHODS
  A 475-bed tertiary cancer center in the southern United States.
  
  
  METHODS
  From April to October 2004, 1,258 surface samples and 627 bioaerosol samples were obtained from 74 HEPA-filtered rooms (in addition, 88 outdoor bioaerosol samples were obtained). Samples were collected from rooms cleaned within 1 hour after patient discharge and from rooms before cleaning. Positive and negative airflows were evaluated using air-current tubes at entrances to patient rooms.
  
  
  RESULTS
  Of 1,258 surface samples, 3.3% were positive for Aspergillus species. Univariate analysis showed no relationship between cleaning status and occurrence of Aspergillus species. Of 627 bioaerosol samples, 7.3% were positive for Aspergillus species. Multiple logistic analysis revealed independently significant associations with detection of Aspergillus species. Cleaned rooms positive for Aspergillus species had a higher geometric mean density of colonies than that of rooms sampled before cleaning (18.9 vs 5.5 colony-forming units [cfu] per cubic meter; P=.0047). Rooms with positive airflow had a detection rate for bioaerosol samples equivalent to that of rooms with negative airflow (7.3% vs 7.8%; P=.8). There was no significant difference in the density of Aspergillus species between rooms with negative airflow and rooms with positive airflow (12.5 vs 8.4 cfu/m(3); P=.33).
  
  
  CONCLUSIONS
  Concentration of bioaerosol contamination with Aspergillus species was increased in rooms sampled 1 hour after cleaning compared with rooms sampled before cleaning, suggesting a possible correlation between re-entrained bioaerosols (ie, those suspended by activity in the room) after cleaning and the risk of nosocomial invasive aspergillosis.
authors.affiliation: Department of Environmental Health and Safety, The University of Texas M. D. Anderson Cancer Center, Houston, TX 77230, USA. ldlee@mdanderson.org
authors.forename: Linda D
authors.initials: LD
authors.lastname: Lee
authors.forename: Matthew
authors.initials: M
authors.lastname: Berkheiser
authors.forename: Ying
authors.initials: Y
authors.lastname: Jiang
authors.forename: Brenda
authors.initials: B
authors.lastname: Hackett
authors.forename: Ray Y
authors.initials: RY
authors.lastname: Hachem
authors.forename: Roy F
authors.initials: RF
authors.lastname: Chemaly
authors.forename: Issam I
authors.initials: II
authors.lastname: Raad
mesh_terms: D000336:Aerosols; D000391:Air Microbiology; D000392:Air Movements; D001230:Aspergillus / Q000302:isolation & purification*; D015169:Colony Count, Microbial; D003428:Cross Infection / Q000517:prevention & control; D004780:Environment, Controlled; D004866:Equipment Contamination; D005374:Filtration / Q000295:instrumentation; D006745:Hospital Bed Capacity, 300 to 499; D006785:Hospitals, University; D006801:Humans; D017053:Infection Control / Q000379:methods*; D010316:Particle Size; D011446:Prospective Studies; D014481:United States; D014691:Ventilation / Q000295:instrumentation*
chemical_list: D000336:Aerosols