Investigation of methods for fungal air monitoring and air quality to estimate baseline acceptable levels in Critical Care Units and azole resistance

Aspergillus species are spore forming, filamentous fungi, ubiquitous in the environment and most often associated with disease in the immunocompromised host. As many healthcare outbreaks have been documented globally, protecting the vulnerable patient from this commonly encountered airborne micro-organism is a challenge. Increased fungal resistance to the azole group of antifungal agents used to treat these infections is also a global concern.

Advances in modern medicine with the use of chemotherapeutic regimens, transplantation medicine and immune-modulating agents has resulted in an increased patient population susceptible to this opportunistic infection. With airways colonisation a risk factor for invasive disease, the microbiome of the built environment and its interactions with its occupants is an important area of study to enable plans to enhance health and wellbeing indoors.

Within healthcare, many strategies exist to protect the vulnerable patient from infections acquired from the hospital environment. These may be incorporated into clinical pathways, infection control policy, or building design. Environmental sampling is often suggested when investigating nosocomial outbreaks or to monitor the environment for breaches in dust prevention measures during building works in hospitals. There is much dispute regarding which methodology to use with some standard methodology requiring specialist skills and equipment not readily available across all institutions across the UK/the globe. A lack of defined thresholds limits for the many different healthcare environment also makes interpretation of results difficult.
More research is required in healthcare to help define protocols for easily accessible testing methods that can provide an early indication of when environmental levels of Aspergillus present a high risk to patients. This will allow remedial actions and preventative measures to be instigated to prevent infection.

We describe a study undertaken across a 12-month period to estimate baseline levels of Aspergillus spp in the environment and the use of particle counting devices to predict environmental contamination over the normal levels for several specialist areas at Wirral University Teaching Hospital with focus on the critical care environment. In addition, antifungal testing will be be performed on representative environmental isolates to determine azole resistance.

Outputs

Publication:
48. Bamber S, Haiduven D, Denning DW. Survey of current national and international guidance to reduce risk of aspergillosis in hospitals. J Hosp Infect. 2025 May;159:124-139. doi: 10.1016/j.jhin.2025.02.015. Epub 2025 Mar 8. PMID: 40064445.

Available at: https://www.journalofhospitalinfection.com/article/S0195-6701(25)00056-8/fulltext

Thesis not complete. Thesis is expected to be by publication.