Fungal aerobiology: how, when and where?

Area of Science:

• Medical Mycology
• Hospital Infection Control
• Environmental Health

Background:

• Hospitalized patients face risks from airborne fungal spores, primarily Aspergillus.
• Infection risk varies significantly based on patient's underlying condition and spore exposure levels.

Purpose of the Study:

• To evaluate the risk of Aspergillus infection in hospitalized patients.
• To determine the effectiveness of environmental controls, such as air filtration, in mitigating infection risk.
• To differentiate risk factors and protective strategies for neutropenic versus non-neutropenic patients.

Main Methods:

• Assessed patient risk based on underlying conditions and degree of immunocompromise.
• Evaluated airborne Aspergillus spore levels using colony-forming units (cfu) per unit of air.
• Reviewed current environmental control strategies, including laminar air flow rooms and HEPA filtration.

Main Results:

• Severely neutropenic patients are highly susceptible to Aspergillus infection even at low spore concentrations, necessitating environmental protection.
• Airborne spore levels (cfu) are unpredictable and monitoring may not alter management if ventilation is adequate.
• For non-neutropenic patients, pre-hospital colonization poses a risk comparable to hospital exposure, diminishing the value of air filtration.

Conclusions:

• Highly filtered environments, such as laminar air flow rooms, are essential for severely immunocompromised patients.
• Routine ventilation system maintenance is crucial for effective environmental control.
• Air filtration offers limited benefit for non-neutropenic patients unless external factors, like nearby construction, increase ambient spore load.