An increase in the number of cases of postoperative empyema due to S. marcescens was recognized in the intensive care unit (ICU) of our Division of Thoracic Surgery between 3 and 19 March 2013. Pleural samples from patients and environmental samples from the operating room and ICU were obtained. A total of eight isolates (six from pleural fluid and two from portable suction devices in ICU) were identified as Serratia marcescens. All isolates were found to be identical by repetitive sequence-based polymerase chain reaction. This is the first report of an outbreak caused by S. marcescens related to a contaminated portable suction machine. (C) 2013 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.