INFECTION PREVENTION
Comparing air and surface contamination levels with new disinfection methods
Dr Andrew Kemp and Dr Vanessa Hodgkinson present a study comparing the bacterial load on surfaces and the air particle counts in a working office environment, after the introduction of two new disinfecting technologies.
Comparative bacterial counts and air particle counts were taken prior to, and post the introduction of two new disinfecting technologies in a busy working office, over a 36 hour period. Both rooms were tested after routine
standard cleaning and before the start of the business day. This was repeated after the introduction of the new technologies into each room to compare the individual effect of each technology on both air and surface contamination levels. Live colony forming unit (CFU) counts were obtained using a Bacteria Specific Rapid Metabolic Assay (BSRMA).1,2
Additionally,
blood agar cultures were used for species identification. Air sampling for particulates was conducted using a particle counter that can identify and individually count multiple particle sizes.
At the end of the 36-hour testing period, both rooms showed significant improvements in air particle and surface contamination levels.
Background Previous testing, showed a significant reduction in surface contamination when both new disinfecting technologies were introduced into a single room.3
CFU counts only. Viruses and fungi were not able to be assessed from surface samples. Whilst not exact, it is possible to extrapolate the bacterial CFU count results with bench top efficacy tests on viruses and fungi, allowing the potential for equivalent increases and decreases of both viral units and fungi4
and therefore the
bacterial CFU counts can be considered a surrogate for all bioburden in this study. Airborne particles of biological origin including, viruses, bacteria and fungi, are commonly present in the air we breathe.5 Pathogens that are able to remain alive after aerosolization and air transport are a potential cause of respiratory disease. These are often associated with other substances to form complex particles.6 An example of a complex particle would be an influenza virion within a droplet composed of mucous, salts and water (a sneeze). Overall small particles containing viruses can remain airborne for long periods of time, allowing for transport to other locations.7
It is understood that air particle counts will include multiple contaminants including, volatile organic compounds
This study
looks at individual effects of each product on both surface contamination and air particulates.
This study is limited to bacterial surface
Two offices of equivalent size with similar footfall, sharing the same ventilation system, were selected. One office was treated using the air handling technology, and one with the persistent surface treatment.
WWW.PATHOLOGYINPRACTICE.COM DECEMBER 2024 41
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