**6. Summary**

species were also identified within the patient rooms of the control zone. *Staphylococcus saprophyticus*, *Staphylococcus epidermidis*, *Staphylococcus capitis*, *Micrococcus luteus*, *Staphylococcus haemolyticus*, *Bacillus clausii*, *Bacillus licheniformis*, *Dermabacter hominis*, *Kocuria palustris*, Gram-positive cocci, Gram-negative rods, *Micrococcus lylae*, and *Staphylococcus hominis* were found in both the recirculating air of the patient room and on the patient remote and HVAC return. Many of the aerosolized pathogens found within the recirculating air were found on the HVAC return vents. Presence of these pathogens on the return vents confirms their aerosolized nature and threat to the clinical spaces also served by the recirculated air. With the exception of *Bacillus licheniformis*, each of these pathogens is associated with patient illness and infections. The sources of the above airborne pathogens are most likely the patients,

It is also important to note that patient rooms in the MIXED Zone received approximately 35% of their recirculated air from the rooms from the LSAR Zone and thus benefited from the installed LAS-APS filtration capacity. The zone also served as an "internal control" as it was located on same the floor as LSAR Zone. Viable yeast was found in the circulating air of the patient rooms in LSAR Zone, and viable *Rhodotorula* was found on the HVAC return vent. Although at a significantly reduced level from that observed in CF-AHU Zone, viable bacteria were identified within the air of the patient rooms of MIXED Zone. *Staphylococcus haemolyticus*, *Dietzia cinnamea*, and *Streptococcus anginosus*, each a potential source of patient illness and infection, were identified in the patient rooms of MIXED Zone. *Bacillus licheniformis* was also identified but is not associated as a source of patient illness or infection. Interestingly, there were no viable bacteria found on the surfaces swabbed in MIXED Zone. VOCs were reduced over that assessed in CF-AHU Zone. The reduction of viable fungi in MIXED Zone corresponded to the simultaneous reduction in

The patient rooms in LSAR Zone received all of their supply and recirculated air from the LAS-APS installation. There were no viable fungi by air or swab detected in the patient rooms in LSAR Zone. Likewise, there were no viable bacteria by air detected in the patient rooms in LSAR Zone. Low levels of *Staphylococcus epidermidis* were found on the IV control faceplate, and *Corynebacterium* and *Staphylococcus capitis* were found on the patient remote. Because no viable bacteria were identified within the air of the patient rooms in LSAR Zone, the surface bacteria identified on the patient remote and IV control faceplate were most likely due to direct surface-to-surface contact. The lowest levels of VOCs were found in the patient rooms of LSAR Zone as these rooms demonstrated no viable fungi in the

The vast majority of infectious surface fomites originate from the air and may be directed onto surfaces by air flow generated by in-room fans and air conditioning systems [44–46]. Consequently, a reduction in airborne bacterial and fungal pathogens should be associated with a reduction in surface fomites [44, 47]. Overall reduction of airborne and surface bacterial and fungal pathogens responsible for patient illness and infections should result in a reduction of associated illnesses, HAI rates, and improved metrics of patient care inclusive of, but not limited to, length of stay and readmission rates. Improvements in these outcome

metrics should, by association, correlate to risk mitigation and cost avoidance.

visitors, and healthcare workers [42, 43].

148 Vignettes in Patient Safety - Volume 4

fungal VOC sources.

circulating air.

In the modern healthcare environment, organizations strive to provide optimal patient experience by improving the quality of patient care, enhancing clinical outcomes, while at the same time containing associated costs. Rarely is there an opportunity to utilize technology that positively impacts quality and cost of hospital care without a detrimental "trade off" or major changes in existing behaviors or protocols. We hypothesized that LAS-APS implementation within the SLUHN facility will lead to notable enhancements in air quality across areas serviced by this air filtration/purification system. The current study clearly demonstrates a significant reduction across all forms of air contamination following the installation of LAS-APS. These results represent an important milestone for further research in this critical and often neglected area of healthcare facility operations and maintenance.
