Outbreak of bloodstream infections because of Serratia marcescens in a pediatric department

Background: Serratia marcescens can cause health care-associated infections. We herewith report the investigation and control of an outbreak of S marcescens bloodstream infections (BSI) in a general pediatric department. Methods: From April to May 2009, temporally related cases of S marcescens BSI occurred in a 40-bed general pediatric department of a tertiary care hospital. An outbreak investigation including case identification, review of medical records, environmental cultures, patients' surveillance cultures, personnel hand cultures, pulsed-field gel electrophoresis, and a case-control study were conducted. Controls were patients without S marcescens BSI but hospitalized in the department for at least 48 hours during the outbreak. Enhanced infection control measures were immediately implemented by the Infection Control Committee. Results: During the study period, 4 patients developed BSI because of a S marcescens strain demonstrating the same antimicrobial susceptibility pattern as well as the same molecular profile. Patients' surveillance cultures and personnel hand cultures were negative. In 1 case-patient, S marcescens grew from cultures of intravenous infusion systems. In the case-control study performed, there were no differences in demographics, intravenously administered medications, or place of hospital stay. Case patients had changes in vascular access significantly more frequently than controls. No S marcescens infections occurred in the department during the 18 months following implementation of the enhanced infection control measures. Conclusion: Prompt recognition and strict adherence to infection control measures are of paramount importance in combating an outbreak of S marcescens bloodstream infection