Acremonium kiliense endophthalmitis that occurred after cataract extraction in an ambulatory surgical center and was traced to an environmental reservoir.

During October and November 1993, four patients contracted Acremonium kiliense endophthalmitis at one ambulatory surgical center. We hypothesized that the source was environmental and conducted a matched case-control study, environmental evaluation, and observational studies. Case and control patients were similar in clinical characteristics. However, case patients all had surgery on the first operative day of the week or had surgery significantly sooner after the operating room opened than did controls (a median of 46 vs. 150 minutes afterward; P = .03). An environmental review revealed the ventilation system was switched on 5-30 minutes before procedures began on the first operative day of the week, and air was filtered before but not after humidification. Cultures of the humidifier water in the ventilation system yielded A. kiliense phenotypically identical to isolates from case patients. Our data suggest that switching on the ventilation system each week aerosolized a reservoir of A. kiliense and caused infection of patients. We believe this is the first reported outbreak of fungal endophthalmitis traced to an environmental source, and it underscores the importance of utilizing established hospital infection control practices in the outpatient setting.