You have been designated as a coordinator of construction of a bone marrow transplant unit (BMTU). There will be extensive removal of walls and floors in order to install the laminar flow rooms required for a BMTU. From the standpoint of frequency and lethality, which of the following fungi should be your biggest concern?

Fungal infections are potentially serious in a bone marrow transplant unit (BMTU), Candida and Aspergillus are the most common causes of infection in BMT patients and both have a risk of mortality. However, the two differ in that Candida is a human commensal and cannot be excluded by construction practices and environmental air monitoring. On the other hand, aspergilli are ubiquitous in the environment. There are instances of multiple infections in new units that have not been monitored prior to opening or in units adjacent to construction projects. Strict precautions should be taken to exclude dust and debris from the BMTU area during construction, but in any event, the environment should be monitored for airborne microorganisms, especially Aspergillus, prior to opening the unit. Zygomycetes may also be present in the air but are a less frequent cause of opportunistic infection in the BMT patient. While Penicillium organisms are also frequent in air, the species associated with opportunistic infection, P. marneffei, is endemic in Southeast Asia where it causes disease in the AIDS patient. Pneumocystis jiroveci is an anthropophilic organism with a human reservoir and, like, Candida not excluded by construction practices. Although particularly recognized for opportunistic infection in AIDS patients, other immunocompromised patients may also have infection, including the occasional BMT patient.