Survey of current national and international guidance to reduce risk of aspergillosis in hospitals.

Aspergillus spp. are most commonly associated with disease in the severely immunocompromised host and those with chronic chest disease. The scope of patients at risk is expanding, including intensive care (inclusive of severe viral pneumonia), trauma, burns and major surgery. As exposure or colonisation is a prerequisite to Aspergillus-related disease, this has prompted a global review of preventative measures recommended in healthcare establishments. This global review includes 75 documents from 24 countries, categorised into clinical, infection prevention and control, and building-related guidance for prevention of invasive aspergillosis (IA). We overview the IA incubation period and different acceptable levels of airborne Aspergilli in protected environments (PE), including critical care and operating rooms. Few documents cover all aspects of prevention, prophylaxis, avoidance, preventative measures and monitoring (environmental and clinical). A multi-disciplinary approach is required to identify and minimise the multiple risks and ensure adequate preventative measures. Most building-related guidance addresses construction and internal hospital alterations, but we also review the importance of good management of the healthcare environment (including ventilation systems) and uncertainties of environmental monitoring. We highlight the differences in standards recommended for protective patient environments including the critical care environment. The large capital investment required for protective environments is often limited to patient groups most at risk. Single document comprehensive guidance is lacking, and many countries provide no guidance. Reduction in healthcare-associated acquisition of invasive aspergillosis during vulnerable in-patient episodes requires heightened awareness of patients at risk, careful risk assessment and attentive maintenance of the general hospital environment.