the highly virulent 2006 norwegian ehec o103h25 outbreak strain is related to the 2011 german o104h4 outbreak strain高毒性2006挪威肠出血性大肠杆菌疫情o103h25应变与2011年德国o104h4爆发压力.pdf

The Highly Virulent 2006 Norwegian EHEC O103:H25 Outbreak Strain Is Related to the 2011 German O104:H4 Outbreak Strain ´ ¤ ˚ Trine M. L’Abee-Lund, Hannah J. Jørgensen , Kristin O’Sullivan, Jon Bohlin, Goro Ligard, Per Einar ¨ Granum, Toril Lindback* Department of Food Safety and Infection Biology, Norwegian School of Veterinary Science, Oslo, Norway Abstract In 2006, a severe foodborne EHEC outbreak occured in Norway. Seventeen cases were recorded and the HUS frequency was 60%. The causative strain, Esherichia coli O103:H25, is considered to be particularly virulent. Sequencing of the outbreak strain revealed resemblance to the 2011 German outbreak strain E. coli O104:H4, both in genome and Shiga toxin 2- encoding (Stx2) phage sequence. The nucleotide identity between the Stx2 phages from the Norwegian and German outbreak strains was 90%. During the 2006 outbreak, stx2-positive O103:H25 E. coli was isolated from two patients. All the other outbreak associated isolates, including all food isolates, were stx-negative, and carried a different phage replacing the Stx2 phage. This phage was of similar size to the Stx2 phage, but had a distinctive early phage region and no stx gene. The sequence of the early region of this phage was not retrieved from the bacterial host genome, and the origin of the phage is unknown. The contaminated food most likely contained a mixture of E. coli O103:H25 cells with either one of the phages. ´ ˚ Citation: L’Abee-Lund TM, Jørgensen HJ, O’Sullivan K, Bohlin J, Ligard G, et al.