Outbreaks of gram-negative bacterial bloodstream infections traced to probable contamination of hemodialysis machines - Canada, 1995; United States, 1997, and Israel, 1997

An investigation into three different cluster incidents in which dialysis patients were diagnosed with gram-negative bacterial blood infections reveals the source to most likely be contaminated waste port drains in the dialysis machines. The machines were all the COBE Centrysystem 3 model, and the investigation showed that some of the one-way valves allowed backflow of contaminated waste into the unit. Instructions for proper maintenance and functioning of the equipment were sent to all machine owners.
During 1996, approximately 236,000 persons received hemodialysis in the United States; of these, an estimated 183,000 (78%) received chronic hemodialysis (1). Patients who receive chronic hemodialysis are at increased risk [...]