title: Non-Seasonal Variation of Airborne Aspergillus Spore Concentration in a Hospital Building.
abstract: Nosocomial fungal infections are gaining increased attention from infectiologists. An adequate investigation into the levels of airborne Aspergillus and other fungal spores in hospital settings, under normal conditions, is largely unknown. We monitored airborne spore contamination in a Swiss hospital building in order to establish a seasonally-dependent base-line level. Air was sampled using an impaction technique, twice weekly, at six different locations over one year. Specimens were seeded in duplicate on Sabouraud agar plates. Grown colonies were identified to genus levels. The airborne Aspergillus spore concentration was constantly low throughout the whole year, at a median level of 2 spores/m³ (inter-quartile range = IQR 1-4), and displayed no seasonal dependency. The median concentration of other fungal spores was higher and showed a distinct seasonal variability with the ambient temperature change during the different seasons: 82 spores/m³ (IQR 26-126) in summer and 9 spores/m³ (IQR 6-15) in winter. The spore concentration varied considerably between the six sampling sites in the building (10 to 26 spores/m³). This variability may explain the variability of study results in the literature.
authors.affiliation: Kantonsspital Aarau AG, Institute for Laboratory Medicine, Tellstrasse 1, 5001 Aarau, Switzerland. michael.oberle@ksa.ch.
authors.forename: Michael
authors.initials: M
authors.lastname: Oberle
authors.affiliation: Analytica Medizinische Laboratorien AG, Falkenstrasse 14, 8024 Zürich, Switzerland. m.reichmuth@analytica.ch.
authors.forename: Markus
authors.initials: M
authors.lastname: Reichmuth
authors.affiliation: Spital Langenthal, Medizinische Klinik, St. Urbanstrasse 67, 4901 Langenthal, Switzerland. r.laffer@sro.ch.
authors.forename: Reto
authors.initials: R
authors.lastname: Laffer
authors.affiliation: Kantonsspital Aarau AG, Institute for Laboratory Medicine, Tellstrasse 1, 5001 Aarau, Switzerland. cornelia.ottiger@ksa.ch.
authors.forename: Cornelia
authors.initials: C
authors.lastname: Ottiger
authors.affiliation: Kantonsspital Aarau AG, Institute for Laboratory Medicine, Tellstrasse 1, 5001 Aarau, Switzerland. hans.fankhauser@ksa.ch.
authors.forename: Hans
authors.initials: H
authors.lastname: Fankhauser
authors.affiliation: Spital Lachen, Klinik für Innere Medizin, Oberdorfstrasse 41, 8853 Lachen, Switzerland. thomas.bregenzer@spital-lachen.ch.
authors.forename: Thomas
authors.initials: T
authors.lastname: Bregenzer
mesh_terms: D000391:Air Microbiology; D001230:Aspergillus / Q000302:isolation & purification*; D005658:Fungi; D006761:Hospitals / Q000706:statistics & numerical data*; D012621:Seasons; D013172:Spores, Fungal / Q000302:isolation & purification*
keywords: Aspergillus; airborne fungal spores; hospital air; monitoring; seasonal variation; spore contamination