Faucet aerators:: A source of patient colonization with Stenotrophomonas maltophilia

Background: Multiple nosocomial outbreaks have been linked to contaminated water sources within the hospital. We report in this article a cluster of patients in a surgical intensive care unit who were colonized or infected with Stenotrophomonas maltophilia. Methods: This study was conducted at an acute care academic hospital. Patients colonized or infected with S maltophilia were identified by prospective surveillance. Environmental isolates were obtained by culturing multiple water sources by using standard techniques. Patient and environmental isolates were examined by pulsed-field gel electrophoresis. Results: Patients were colonized with 2 isolates of S maltophilia, which were found by pulsed-field gel electrophoresis to be identical to strains isolated from the faucet aerators present in sinks in the patients' rooms. Multiple different strains, as defined by pulsed-field gel electrophoresis, were isolated from patients during this outbreak. Conclusions: We believe that Low level contamination of our potable water led to contamination of the faucet aerators with subsequent bacterial amplification on the aerator, which led to contamination of water after aeration. Cultures should be performed on faucet aerators when water sources are suspected as the reservoir for a nosocomial outbreak. If additional clusters of infected or colonized patients are linked to contaminated aerators, consideration should be given to routine disinfection or removal of the aerators.