Multi-prong approach to control construction-related Aspergillus infections

Background: Excavation and works done during renovation and construction pose risks of healthcare-associated Aspergillus infections to immunocompromised patients in the healthcare setting. Hence, infection control measures are commonly implemented to mitigate the risk.  Common confinement measures include building temporary walls and ceilings to isolate areas being renovated from patients’ care areas and other equally essential services areas, such as operating rooms, pharmacy and intensive care units.

Objective:  With the recent increased number of major building projects around the Singapore General Hospital (SGH), we introduced interventions to enhance our infection control measures related to building and construction.

Methods: At SGH, a 1600-bed acute tertiary care hospital in Singapore, the ‘Infection Control Risk Assessment Matrix’ (ICRA) is used by project officers from the Facilities Development and Faculties & Plant Engineering to assess the risks involved during their building or renovation projects.  Appropriate measures are then determined for implementation prior to the start of renovation or building.  High risk projects (Class III or IV) will require discussion with the Infection Control (IC) team to walk through the precautionary measures.  A structured ‘Renovation and Construction Course’ is held annually to train Infection Control Liaison Officers, nursing managers and staffs from the two Facilities departments in the use of the ICRA. Currently, near and around the surroundings of the hospital there are ongoing major constructions of new buildings for the Duke-National University of Singapore Graduate Medical School and the Pathology Building. Eighty five units of portable HEPA filters were procured and installed as adjunct preventive measure at high risk areas with immunocompromised patients.  Close monitoring of Aspergillus counts in the air at the clinical areas are conducted on a 6-monthly basis.

Results: The incidence rates of Aspergillosis in pre-installation period (Dec 05 to Nov 06) and in the post-installation period (Dec 06 to Jun 08) at wards with portable HEPA units were 39.55 and 21.88/100,000 patient days respectively (p = 0.018). In comparison, in the wards installed with non-portable HEPA filtration, the incidence rates were 34 and 35.45 for the two periods respectively (p>0.5).

Conclusions: The close collaboration between the Facilities departments and Infection Control Unit help to mitigate the risks of nosocomial Aspergillosis during building and construction activities.