Filamentous Fungi in a Tertiary Care Hospital Environmental Surveillance and Susceptibility to Antifungal Drugs

Abstract

Objective.To evaluate filamentous fungi with respect to environmental load and potential drug resistance in a tertiary care teaching hospital.Design.Monthly survey in 2 buildings of the hospital during a 12-month period.Setting.Hippokration Hospital in Thessaloniki, Greece.Methods.Air, surface, and tap water sampling was performed in 4 departments with high-risk patients. As sampling sites, the solid-organ transplantation department and the hematology department (in the older building) and the pediatric oncology department and the pediatric intensive care unit (in the newer building) were selected.Results.From January to May of 2000, the fungal load in air (FLA) was low, ranging from 0 to 12 colony-forming units (cfu) per m3 in both buildings. During the summer months, when high temperature and humidity predominate, the FLA increased to 4-56 cfu/m3. The fungi commonly recovered from culture of air specimens wereAspergillus niger(25.9%),Aspergillus flavus(17.7%), andAspergillus fumigatus(12.4%). Non-Aspergillusfilamentous fungi, such asZygomycetesandDematiaceousspecies, were also recovered. The pediatric intensive care unit had the lowest mean FLA (7.7 cfu/m3), compared with the pediatric oncology department (8.7 cfu/m3), the solid-organ transplantation department (16.1 cfu/m3), and the hematology department (22.6 cfu/m3). Environmental surfaces were swabbed, and 62.7% of the swab samples cultured yielded filamentous fungi similar to the fungi recovered from air but with low numbers of colony-forming units. Despite vigorous sampling, culture of tap water yielded no fungi. The increase in FLA observed during the summer coincided with renovation in the building that housed the solid-organ transplantation and hematology departments. All 54Aspergillusair isolates randomly selected exhibited relatively low minimum inhibitory or effective concentrations for amphotericin B, itraconazole, voriconazole, posaconazole, micafungin, and anidulafungin.Conclusion.Air and surface fungal loads may vary in different departments of the same hospital, especially during months when the temperature and humidity are high. EnvironmentalAspergillusisolates are characterized by lack of resistance to clinically important antifungal agents.