An outbreak of Aspergillus infection at a tertiary care hospital was identified among inpatients who had amputation wounds, peritonitis, allograft nephritis, or mediastinitis. During a 2-year period, 6 patients were identified, all of whom had Aspergillus species recovered from samples from normally sterile sites. All cases clustered in the operating theater during a single 12-day period. To assess operating theater air quality, particle counts were measured as surrogate markers for Aspergillus conidia. A substantial increase in the proportion of airborne particles > or =3 microm in size (range, 3-fold to 1000-fold) was observed in many operating rooms. A confined space video camera identified moisture and contamination of insulating material in ductwork and variable airflow volume units downstream of final filters. No additional invasive Aspergillus wound infections were identified after the operating theater air-handling systems were remediated, suggesting that this unusual outbreak was due to the deterioration of insulating material in variable airflow volume units.

DNA was successfully isolated from numerous Aspergillus spp. by use of a commercial kit. DNA that was easily digested and yielded PCR products up to 8.5 kb in size was recovered from broth or agar cultures. The ease and speed of this protocol provide an alternative to physical methods of DNA isolation.Aspergillus fumigatus is a filamentous acscomycetous fungus that is ubiquitous in nature. In recent years the aspergilli have become an increasingly frequent cause of life-threatening opportunistic infections (7,8,11,12). Consequently, there is a growing interest in the molecular biology of this fungus, which has been accelerated by the genome-sequencing project (6). Although relatively new, a broad range of molecular manipulations of A. fumigatus are now possible, including gene disruption, various PCR applications (random amplified polymorphic DNA analysis, microsatellite typing, etc.), and DNAbased epidemiological studies (restriction fragment length polymorphism analysis, fingerprinting, etc.) (1-3, 5, 13-15). Each of these techniques requires the recovery of good-quality genomic DNA.Most DNA extraction protocols for Aspergillus spp. rely on mechanical isolation methods that employ grinding mycelia after freezing them in liquid nitrogen or glass bead disruption, followed by additional purification steps (9). We routinely isolate DNA from many types of fungi by a variety of different techniques. These techniques range from simple boiling, which can yield small amounts of DNA within minutes, to bead bashing, which increases yield but also increases time, to spheroplasting, which can take two or more days but yields large amounts of high-purity high-molecular-weight DNA (4). In an effort to identify a method that was as simple as bead beating, that had as high a yield as spheroplasting, and that had as high a throughput as boiling, we investigated a chemical-based method (MasterPure yeast DNA purification kit [Epicentre, Madison, Wis.]) and found that with modification, this method is convenient and easy to use, does not require physical methods, and works with mycelia or conidia.Strains and growth conditions. The strains used in this study are listed in Table 1. Stock cultures were grown on potato dextrose agar (PDA) plates (24 g of PD [Difco, Detroit, Mich.]/liter, 20 g of agar/liter) at 30°C. Mycelial cultures were harvested from PD broth grown for 8 to 24 h in 10-ml tubes (3 ml of culture) or 125-ml flasks (40 ml of culture) at 30°C (225 rpm) by filtering them through Whatman paper (Fisher Scientific, Inc., Pittsburgh, Pa.), washed according to the manufacturer's instructions, and then blotted dry. Conidial cultures were prepared from PD agar plates grown for 3 to 11 days at 30°C and harvested by washing with 10 ml of sterile 0.1%