Deadly: Outbreaks in the hemodialysis setting
One break is all it takes
Concerned about rising vancomycin resistance and a growing patient population in dialysis, public health officials are taking a hard look at infection control problems in the setting.
The following thumbnail sketches of historical outbreaks in dialysis centers were taken from a presentation recently in San Diego at the Interscience Conference on Antimicrobial Agents and Chemo-therapy (ICAAC).1 The outbreaks were presented by Jerome Tokars, MD, MPH, chief of the new dialysis surveillance system at the Centers for Disease Control and Prevention:
Ten episodes of Enterobacter cloacae bloodstream infection occurred at a dialysis center in Canada. Investigation showed that each dialysis machine had a waste-handling option (WHO) through which dialyzer-priming fluid was discarded before dialysis. One-way valves in the WHO had become incompetent, allowing the units to become contaminated by backflow. Similar outbreaks were later reported at least three other dialysis centers.
One-hundred-and-one patients at a dialysis center in Brazil had acute liver failure, and 50 died. Water used for dialysis was obtained from a local reservoir and brought to the center in a tanker truck, but was not treated adequately before use. Microcystins produced by cyanobacteria were the cause of the outbreak, having been found in water from the reservoir, water from the dialysis center, and serum and liver tissue from case patients.
Thirty patients at three dialysis centers in different U.S. states developed hemolysis while undergoing hemodialysis, and two died. The outbreak was traced to use of hemodialysis blood tubing with a manufacturing defect that caused a narrowing of the aperture through which blood was pumped. After a voluntary recall of the implicated tubing sets, there were no further patient symptoms.
Ten bloodstream infections due to Serratia liquefaciens occurred at one dialysis center. These infections occurred because preservative-free vials of erythropoietin, intended for single use, had been punctured multiple times and residual drug pooled into a common vial. There is a strong economic incentive to engage in this practice, and it has become common at many dialysis centers.
Sixteen patients at one dialysis center developed chills, nausea, or vomiting; all were hospitalized, and two died. The investigation revealed that recommended maintenance of the reverse osmosis membrane, used to purify water before hemodialysis, had not been performed. A sulfuric odor was noted near the reverse osmosis unit, and volatile sulfur-containing compounds (e.g., sulfur dioxide) were found in the water. These sulfur-containing compounds are known to cause multiple nonspecific symptoms such as those experienced by case-patients, but this was the first instance of probable human parenteral exposure.
1. Tokars JI. Recent outbreaks in dialysis settings. Abstract: 409. 42nd Interscience Conference on Antimicrobial Agents and Chemotherapy. San Diego; Sept. 27-30, 2002.