A nosocomial outbreak of febrile bloodstream infection caused by heparinized-saline contaminated with Serratia marcescens, Tokyo, 2002.

In January 2002, 12 patients with Serratia marcescens bloodstream infection (BSI) were identified in a hospital in Tokyo, Japan. We conducted an epidemiological investigation of this outbreak. We undertook a medical-records review and employee interviews, and performed a case-control study to determine risk factors for S. marcescens BSI. An observational study of the hospital's procedures and an environmental microbiologic sampling were performed. We identified 12 suspected and 12 confirmed patients with S. marcescens BSI, including 7 who died. A case-control study showed that vascular access devices (odds ratio [OR] = 30.46; 95% confidence interval [CI] = 3.5-685.6) and the use of heparin-locks, between December 26 and January 15 (OR = 25.7; 95% CI = 2.3-680.4) were significant risk factors for S. marcescens BSI. The observational study revealed multiple lapses in infection control, including use of multi-dose vials of heparin. The outbreak strain was isolated from a hand-towel in the nurse station. The use of multi-dose vials of heparinized-saline during a particularly busy period was associated with BSI risk. The results underscore the risks inherent in infection-control lapses and the use of multi-dose vials.