Intensified colonisation screening according to the recommendations of the German Commission for Hospital Hygiene and Infectious Diseases Prevention (KRINKO): identification and containment of a Serratia marcescens outbreak in the neonatal intensive care unit, Jena, Germany, 2013-2014.

PURPOSE: In 2013, the German Commission for Hospital Hygiene and Infectious Disease Prevention (KRINKO) stated that extending weekly colonisation screening from very low birth weight (VLBW) infants (<1500 g) to all patients in the Neonatal Intensive Care Unit (NICU) might be useful. METHODS: After implementing this recommendation, we detected a previously unnoticed cluster of Serratia marcescens. Strains were typed by Pulsed Field Gel Electrophoresis (PFGE). RESULTS: Over 6 months, 19 out of 159 infants acquired S. marcescens. Twelve of the nineteen patients with S. marcescens were non-VLBW infants, and they were colonised significantly earlier than were VLBW infants (median 17 vs. 28 days; p < 0.01). Molecular typing revealed a polyclonal outbreak with multiple strain types leading to one or two transmissions each and a dominating outbreak strains being involved in an explosive outbreak involving eight neonates. CONCLUSION: The revised KRINKO recommendation may help identify unnoticed outbreaks. Colonised non-VLBW patients may be an underestimated source of S. marcescens.