Inactivation of bacterial and fungal spores by UV irradiation and gaseous iodine treatment applied to air handling filters.

Details

• Personal Author:
  Grinshpun SA ; Indugula R ; Nakpan W ; Reponen T ; Yermakov M
• Description:
  Exposure to viable bacterial and fungal spores re-aerosolized from air handling filters may create a major health risk. Assessing and controlling this exposure have been of interest to the bio-defense and indoor air quality communities. Methods are being developed for inactivating stress-resistant viable microorganisms collected on ventilation filters. Here we investigated the inactivation of spores of Bacillus thuringiensis var. kurstaki (Btk), a recognized simulant for B. antracis, and Aspergillus fumigatus, a common opportunistic pathogen used as an indicator for indoor air quality. The viability change was measured on filters treated with ultraviolet (UV) irradiation and gaseous iodine. The spores were collected on high-efficiency particulate air (HEPA) and non-HEPA filters, both flattened for testing purposes to represent "surface" filters. A mixed cellulose ester (MCE) membrane filter was also tested as a reference. Additionally, a commercial HEPA unit with a deep-bed (non-flattened) filter was tested. Combined treatments of Btk spores with UV and iodine on MCE filter produced a synergistic inactivation effect. No similar synergy was observed for A. fumigatus. For spores collected on an MCE filter, the inactivation effect was about an order of magnitude greater for Btk compared to A. fumigatus. The filter type was found to be an important factor affecting the inactivation of Btk spores while it was not as influential for A. fumigatus. Overall, the combined effect of UV irradiation and gaseous iodine on viable bacterial and fungal spores collected on flat filters was found to be potent. The benefit of either simultaneous or sequential treatment was much lower for Btk spores embedded inside the deep-bed (non-flattened) HEPA filter, but for A. fumigatus the inactivation on flattened and non-flattened HEPA filters was comparable. For both species, applying UV first and gaseous iodine second produced significantly higher inactivation than when applying them simultaneously or in an opposite sequence. [Description provided by NIOSH]
• Subjects:
  Aerosols Fungi Microbiology Occupational Health Safety Ventilation
• Keywords:
  Aerosols; Bacteria; Aerosol Particles; Microorganisms; Ventilation Equipment; Pathogens; Ultraviolet Light; Iodine; Fungi; HEPA Filters; High-efficiency Particulate Air Filters; Author Keywords: Spore; Filter; Ultraviolet; Iodine; Inactivation
• ISSN:
  0048-9697
• Document Type:
  Text
• Funding:
  Grant
• Genre:
  Journal Article
• Place as Subject:
  Ohio ; OSHA Region 5
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  59-65
• Volume:
  671
• NIOSHTIC Number:
  nn:20065080
• Citation:
  Sci Total Environ 2019 Jun; 671:59-65
• Contact Point Address:
  Sergey A. Grinshpun, Center for Health-Related Aerosol Studies, Department of Environmental Health, University of Cincinnati, Cincinnati, OH 45267, USA
• Email:
  sergey.grinshpun@uc.edu
• CAS Registry Number:
  Iodine (CAS RN 7553-56-2)
• Federal Fiscal Year:
  2019
• Performing Organization:
  University of Cincinnati
• Peer Reviewed:
  True
• Start Date:
  20050701
• Source Full Name:
  Science of the Total Environment
• End Date:
  20260630
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:a4b73901c74de044f0803e0ad2c7f4dec756c02d1a75891b955f727caf665251890e790bfc7e74f15c6f6757a5efdeaed2a48f277d8491b9a4538e9d0668e08b
• Download URL:
  https://stacks.cdc.gov/view/cdc/249321/cdc_249321_DS1.pdf
• File Type:
  [PDF - 1.23 MB ]