Contaminated product water as the source of Phialemonium curvatum bloodstream infection among patients undergoing hemodialysis.

OBJECTIVE: We investigated a cluster of cases of bloodstream infection (BSI) due to the mold Phialemonium at a hemodialysis center in Illinois and conducted a cohort study to identify risk factors.
DESIGN: Environmental assessment and cohort study.
SETTING: A hemodialysis center in a tertiary care hospital.
METHODS: A case patient was defined as a person who underwent dialysis at the center and had a blood sample that tested positive for Phialemonium curvatum on culture. We reviewed microbiology and medical records and tested water, surface, and dialysate samples by culture. Molds isolated from environmental and clinical specimens were identified by their morphological features and confirmed by sequencing DNA.
RESULTS: We identified 2 case patients with BSI due to P. curvatum. Both became febrile and hypotensive while undergoing dialysis on the same machine at the same treatment station, although on different days. Dialysis machines were equipped with waste handling option ports that are used to discard dialyzer priming fluid. We isolated P. curvatum from the product water (ie, water used for dialysis purposes) at 2 of 19 treatment stations, one of which was the implicated station.
CONCLUSION: The source of P. curvatum was likely the water distribution system. To our knowledge, this is the first report of patients acquiring a mold BSI from contaminated product water. The route of exposure in these cases of BSI due to P. curvatum may be related to the malfunction and improper maintenance of the waste handling option ports. Waste handling option ports have been previously implicated as the source of bacterial BSI due to the backflow of waste fluid into a patient's blood line. No additional cases of infection were noted after remediation of the water distribution system and after discontinuing use of waste handling option ports at the facility.