Air Date: 10-26-2012| Episode: 261
Dr. Catherine Noakes, PhD, CEng is the Director of Pathogen Control Engineering Institute at the School of Civil Engineering, University of Leeds. Dr. L Fletcher is a research fellow in the School of Civil Engineering at the University of Leeds…
Dr. Catherine Noakes, PhD, CEng is the Director of Pathogen Control Engineering Institute at the School of Civil Engineering, University of Leeds. She is also the Leader of Aerobiology and Infection Control Research Group at the University of Leeds. Dr. L Fletcher is a research fellow in the School of Civil Engineering at the University of Leeds. The Aerobiology and Infection Control Group is a multi-disciplinary research team comprising microbiologists, engineers and mathematical modelers. The group has considerable experience in evaluating bioaerosols in indoor environments and engineering measures to control infection. Their Research is driven by the continuing problem of hospital acquired infection and the worldwide health concerns about infectious diseases spread through airborne routes. Airborne transmission is known to be a primary mechanism in the transmission of TB and influenza, but has also been implicated in the transmission of nosocomial infections including MRSA, Acinetobacter spp, C. difficile and norovirus. In addition, contamination of the environment through contact with dirty hands and objects or airborne dispersal provides a potential reservoir of pathogens which could subsequently cause infection by indirect contacts. Regardless of the pathogen, successful control of infection involves breaking the chain of transmission, for which it is necessary to understand both the mode of transmission as well as the nature of the pathogen and its behavior in the environment. Understanding this complex interaction between people, pathogens and the built environment is at the heart of their research.
Hospital Acquired Infection
The Pathogen Control Engineering Institute at the School of Engineering at University of Leeds uses a multidisciplinary research approach to study hospital acquired infections [HAIs]. On today’s episode of IAQradio, we discussed the program with the institute’s director Catherine Noakes, PhD, CEng and her colleague applied microbiologist Louise Fletcher, PhD.
Nuggets mined from today’s episode:
•Environmental contamination: occurs, is dispersed, settles and contaminates, spreads when touched and re-contaminates.
•Released particles settle everywhere.
•Disposition of particles is predictable.
•Released pathogens can contaminate surfaces far away.
•Risk posed by contaminated surfaces is unknown
•Worst pathogen contamination is normally found closest to the source. AFD’s work best when located close to the source.
•Airborne microbes are susceptible to UV, ozone and negative ions.
•Activities within a hospital such as nurse and doctor rounds, bed-making, patient visitation, all have an effect on the surface and air contamination within the hospital.
•UV is directional, so it is difficult to flood an entire room with UV.
•MRSA and C.Diff are susceptible to UV, hydrogen peroxide and ozone.
•The Institute is engaged in a 5 year study on the relationship between contaminants and airflows within a hospital setting.
•From continent to continent there are similarities between hospital rooms, E.g.: share similar size, similar furnishings. Differences in ventilation, some UK hospitals use natural ventilation. Hospitals in the UK don’t re-circulate air, they introduce fresh air only.
•Some things which seem to make common sense are difficult to prove, such as the effect of single occupancy versus double occupancy on hospital acquired infection HAI.
•Some technology makes promises which in the real world are unrealistic. Most devices are tested by comparing germs going in to viable germs coming out. In the real world it’s “hard to persuade air to enter the device.”
•Devices which emit something (ozone, negative ions, antimicrobials) may perform slightly better than those that don’t as they don’t rely on the air passing through the device.
•Media exaggeration of the danger of HAIs.
•Manufacturers prey on heightened consumer awareness to HAIs, causing consumers to invest in costly equipment which is unnecessary.
•Risk versus reward. Not all microorganisms are dangerous.
•Does introducing clean air into contaminated areas make financial sense?
•Hand hygiene works, UV works, ventilation works, partitions between beds work. · There is a difference between routine daily cleaning and terminal or post occupancy cleaning due to presence of occupants.
•Emitting devices which effectively flood rooms with potent biocides are effective, but potent biocides are hazardous to humans.
•Ozone limonene hydroxyl generators produce nano-particles which are very harmful.
Closing comments: open windows, wash hands and clean surfaces.
Today’s music: “Attack of the Killer Germs” by Neiman Group
Z-Man signing off