Endemic nosocomial Gram-negative bacteraemias resulting from contaminationof intravenous heparin infusions

Following several cases of Gram-negative bacteraemia secondary to intraveno us heparin infusion contamination, we retrospectively reviewed nosocomial b acteraemias associated with heparin infusions at our institution. Thirty-on e episodes of heparin-infusion related bacteraemia occurred in 30 patients over a 23-month period affecting 2% patients receiving heparin infusions fo r more than 48 h. Gram-negative bacteria were responsible for all bacteraem ias. The care of infusions during clinical use was prospectively surveyed, revealing that approximately 20% of lines and cannulae were left for more t han 72 h before replacement, and significant discordance occurred between l ine replacement and syringe and cannula exchange. We concluded that contami nation of the infusions was probably extrinsic and secondary to manipulatio ns of the system during use. Prolonged usage and discordant exchange of inf usion components were likely important factors in initial contamination and subsequent bacterial proliferation. The problem resolved following the int roduction of a policy for routine and simultaneous replacement of lines and syringes at 24-h intervals and upon cannula exchange.