Polymicrobial gram-negative bacteremia associated with saline solution flush used with a needleless intravenous system

Background: During a 2-week period, seven cases of nosocomial polymicrobial gram-negative rod bacteremia occurred on a 39-bed medical and cardiac step-down unit. Combinations of Enterobacter cloacae (seven isolates), Klebsiella pneumoniae (five isolates), and Citrobacter freundii (two isolates) were isolated from blood cultures. Methods: Concurrent and retrospective chart reviews were used to look for further cases and common exposures. Epidemiologic methods were used to refine determination of common exposure. Restriction enzyme DNA analysis was performed on the isolates. Results: Concurrent and retrospective chart reviews revealed four additional possible cases during the same period. All case patients were exposed, through peripheral saline solution locks or central venous catheters, to saline solution “flush” from a central 0.9% saline solution bag and a needleless dispensing pin. Epidemiologic methods implicated probable extrinsic contamination of a single bag and pin used during a 24- 48-hour period (Fisherʹs Exact Test, p< 0.002). There were no other common exposures. Restriction enzyme DNA analysis of the isolates further supported a common source for the outbreak. Conclusions: The introduction of needleless intravascular systems has been embraced for employee protection. Our report is the first to raise the question of patient safety with such systems. This outbreak highlights the inherent risks in rapid introduction of new technologies and points out the delicate balance among patient health, employee safety, and cost containment.