Seventh external quality assessment scheme for Salmonella typing

This report presents the results of the seventh round of the external quality assessment (EQA-7) scheme for typing of Salmonella enterica spp. enterica organised for laboratories in the Food- and Waterborne Diseases and Zoonoses network (FWD-Net). Since 2012, the EQA scheme has covered the molecular typing methods used for EU-wide surveillance, Pulsed Field Gel Electrophoresis (PFGE) for all serovars and Multiple Locus Variable number of tandem repeat Analysis (MLVA) for S. Typhimurium. The EQA-7 scheme was arranged by the Unit of Foodborne Infections at Statens Serum Institut (SSI), Denmark. The current EQA represents the final deliverable under the framework contract with ECDC and was performed between October 2015 and February 2016. Salmonellosis was the second most commonly reported zoonotic disease in the European Union (EU) with a notification rate of 23.4 cases per 100 000 population in 2014. From 2008 to 2014, there was a decrease in the annual total number of Salmonella outbreaks within the EU. However, Salmonella was still the second most common cause of foodborne outbreaks in the EU in 2014. Since 2007, ECDC's Food- and Waterborne Diseases and Zoonoses (FWD) Programme has been responsible for the EUwide surveillance of salmonellosis, including facilitating the detection and investigation of foodborne outbreaks. Surveillance data, including some basic typing parameters for the isolated pathogen, are reported by the Member States to the European Surveillance System (TESSy). In 2012, more advanced and discriminatory molecular typing data were incorporated into TESSy (TESSy-MSS - molecular surveillance system) to improve surveillance of foodborne infections. This molecular surveillance system relies on the capacity of the FWD-Net laboratories to produce comparable typing results. Currently, data from PFGE, which is the gold-standard for Salmonella typing used for EU-wide surveillance, and MLVA are collected in TESSy. The objectives of the EQA scheme are to assess the quality and comparability of the typing data produced by the national public health reference laboratories in the FWD-Net. Test strains for the EQA were selected to cover strains currently relevant for public health in Europe. A set of ten strains was selected for each method - i.e. different Salmonella serovars for PFGE and S. Typhimurium strains for MLVA.