When a new hospital opened in 1983, environmental culturing for Aspergillus organisms and surveillance for nosocomial aspergillosis cases were begun to characterize the relationship between environmental contamination and infection. Monthly air sampling demonstrated increasing concentrations of Aspergillus flavus and Aspergillus fumigatus to mean levels greater than 1 cfu/m3 during 1986-1987, accompanied by a progressive increase in incidence of aspergillosis to 1.2% in immunocompromised patients. This prompted an inspection that revealed heavy growth of Aspergillus organisms on air filters. Subsequent inspections of hospital wards showed small foci of A. flavus growth on other materials. Removal of the contaminated filters and improved environmental maintenance were associated with reduction in A. flavus and A. fumigatus to 0.01 cfu/m3 and a fourfold decline in aspergillosis incidence during the next 2 years. These findings, together with laboratory studies that showed aspergilli could proliferate on common hospital materials when moistened, indicate a need for careful environmental maintenance.

Five cases of nosocomial Legionnaires' disease which occurred over a five-month period were retrospectively investigated. Chart review showed that during the two- to 10-day incubation period before the onset of illness, all of the patients inhaled aerosolized tap water from jet nebulizers (four patients) or from a portable room humidifier (one patient), and all received high dosages of corticosteroids or adrenocorticotropic hormone. Exposure to both factors was highly significant (P less than 0.000001) when compared with the rate of exposure in 69 control patients. Environmental cultures yielded Legionella pneumophila from tap water and from reservoirs of tap water-filled respiratory devices. The yield was highest from hot tap water, in which the free chlorine level was less than 0.05 parts per million. Thus, Legionnaires' disease may be caused by contaminated aerosols from respiratory devices, and the use of contaminated tap water in such devices represents a previously unrecognized hazard to which corticosteroid-treated patients should not be exposed.

A culture survey of hot-tap water systems in 95 apartments and houses in one area of Chicago showed that 30 (32%) were contaminated by Legionella pneumophila, ranging in concentration from 1 to 10(4) organisms/liter. Culture-positive and -negative systems differed significantly only in hot-tap water temperature (P less than .005), which was less than 60 C for all positive specimens. A questionnaire and serosurvey of a subject at each residence showed no cases of pneumonia while he or she lived in the residence and no association of high titers of antibodies to L. pneumophila with positive tap water cultures. Virulence of selected tap water isolates of L. pneumophila in embryonated eggs was similar to that of clinical isolates. In the area studied, residential hot-tap water systems maintained at less than 60 C are frequently contaminated by L. pneumophila, but systems with low levels of contamination (less than or equal to 10(4) organisms/liter) appear not to be an important source of infection of healthy individuals.

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We describe the clinical course of four patients who had Trichosporon mycotoxinivorans recovered from multiple sputum cultures over time with various clinical consequences but no fatalities. We also report successful rapid identification of this organism using matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry. CASE REPORTS