Pseudo-Outbreak of Bloodstream Infections by Serratia mercescens

Cha, Kyeong Sook; Yoo, So Yeon; Wie, Seong Heon; Kim, Ki Yu; Kim, Soo Young

Abstract

BACKGROUND: Serratia marcescens proliferates well in a humid environment or soil and is recently considered as an important pathogen for the severe nosocomial infections. this organism is spreads easily by hand-to-hand transmission, and contaminates medical equipment used for invasive procedures, working environment, medications, and soap.
METHODS
We investigated the source of an outbreak of bloodstream infections by S. marcescens isolated that occurred during the period from July to December, 2004, at a university hospital in Gyeonggi Province and attempted to intervene in the outbreak and control it.
RESULTS
From July to December, 2004, S. marcescens grew from 296 blood culture from 283 patients. The medical charts of the patients were reviewed, and surveillance cultures were taken to identify the outbreak of nosocomial infections and risk factors. Only four cases of infection were identified and all remaining positive blood cultures were due to contamination. Nine isolates randomly selected from the 296 S. marcescens showed an identical pulsed-field gel electrophoresis pattern. To identify the source of infection, environmental culture and hand cultures of the related medical workers were carried out, but S. marcescens was not isolated.
CONCLUSION
As the result of aggressive infection control activities, such as re-education on environmental management methods, hand washing techniques, and blood culture sampling techniques, no more S. marcescens had been grown in blood culture since January, 2005.