Airborne bacteria and fungal spore assessments: Royal Melbourne Hospital
Summary of works
ESG Environmental Pty Ltd (ESG) was engaged by Melbourne Health in 2015 to undertake airborne bacteria and fungal spore assessments at the Royal Melbourne Hospital.
Compliance air testing to ensure safe levels below guideline criteria is best practice and should be undertaken prior to the commissioning of hospital rooms, operating theatres and wards.
Upon completion of the sterile clean, ESG is able to complete the air sampling within a reasonably short period of time.
The time taken to complete the air sampling depends on a number of factors including:
Number of rooms to be sampled and the size of the room to be assessed. Typically one air sample is collected per room unless the size of the room is deemed large enough to warrant more than one. Additional air samples are also collected from another location usually outside the hospital and a control blank for background data and comparative purposes.
The air exchange rate per hour. The recommended delay period for 20 air exchanges per hour is 15 minutes prior to the activation of the air monitors. This ensures sufficient air volume has been exchanged prior to air sampling. Sampling times per location at the RMH have ranged between 15-30 minutes.
After the air samples are collected, the agar plates are sent to the NATA accredited laboratory, usually on the same day. The samples must be incubated for up to 5 days, therefore laboratory results are typically available and reported within 5-6 days of receipt of samples. Provided no anomalous results are detected, ESG is able to provide a letter report of the sampling results within a day of receiving final results from the laboratory.
Currently there is a lack of guidance on specific and clear trigger levels. Therefore ESG has developed and adopted appropriate target, alert and action levels based on published papers and guidelines for hospital airborne infection control to analyse and evaluate the data.
Should the results indicate levels above the adopted criteria for alert and action levels, additional sampling where the same process is replicated will be completed 7 days later to validate the initial testing results and to determine whether bacteria or fungi levels have increased over time.
Other measures and actions may be recommended by ESG such as completion of another sterile clean, testing of the air handling units to ensure positive air pressures, testing and checking of door seals to the room entrances, and to restrict access to sterile areas
Project highlights
Client: Melbourne Health
Client contact: Leanne Chappell
Duration: 2015 – on-going
Specific issues / problem solving
Undertaking the appropriate air sampling tests immediately after the completion of a sterile clean of the areas to be assessed to ensure safe levels below guideline criteria, prior to the commissioning of hospital rooms, operating theatres and wards.
Compliance monitoring and testing of hospital air quality in accordance with relevant guidelines.
Air sample testing was also completed to confirm the efficiency and performance of hospital air purifying systems to ensure positive pressure and adequate exchange of air.
Key services
Development of trigger levels based on guidelines.
Visual inspection to ensure adequate cleaning of testing areas and noting any evidence of mould, dust, dirt or moisture.
Recording of ambient air temperature and humidity levels of each sampling location to ensure they are within the recommended range for hospital environments.
Viable airborne bacteria and fungal/mould spore testing using agar plates and remotely operated two standard SKC single stage impactors.
Air-O-Cell Spore Trap sampling for the collection of non-viable bioaerosols, if necessary for faster turn around time of results.
Where necessary, completion of swab sampling of surfaces to ensure satisfactory levels below guideline.
Air testing was also completed to confirm positive pressure and efficiency of air purifying systems.
Recommendations for routine microbial monitoring.
Reporting of test results and outcomes for hospital requirements and records.
Benefits
Assessment of air quality within hospital theatre rooms and wards prior to commissioning in accordance with relevant guidelines and meeting regulatory requirements.
Confirmation of positive pressure to ensure safe air quality is maintained and test the efficiency and performance of air purifying systems.