title: Molecular Typing and Epidemiology of Human Listeriosis Cases, Denmark, 2002-2012.
abstract: Denmark has a high incidence of invasive listeriosis (0.9 cases/100,000 population in 2012). We analyzed patient data, clinical outcome, and trends in pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) of Listeria monocytogenes strains isolated in Denmark during 2002-2012. We performed 2-enzyme PFGE and serotyping on 559 isolates and MLST on 92 isolates and identified some correlation between molecular type and clinical outcome and patient characteristics. We found 178 different PFGE types, but isolates from 122 cases belonged to just 2 closely related PFGE types, clonal complex 8 and sequence type 8. These 2 types were the main cause of a peak in incidence of invasive listeriosis during 2005-2009, possibly representing an outbreak or the presence of a highly prevalent clone. However, current typing methods could not fully confirm these possibilities, highlighting the need for more refined discriminatory typing methods to identify outbreaks within frequently occurring L. monocytogenes PFGE types.
authors.forename: Anne Kvistholm
authors.initials: AK
authors.lastname: Jensen
authors.forename: Jonas T
authors.initials: JT
authors.lastname: Björkman
authors.forename: Steen
authors.initials: S
authors.lastname: Ethelberg
authors.forename: Kristoffer
authors.initials: K
authors.lastname: Kiil
authors.forename: Michael
authors.initials: M
authors.lastname: Kemp
authors.forename: Eva Møller
authors.initials: EM
authors.lastname: Nielsen
mesh_terms: D002999:Clone Cells; D004269:DNA, Bacterial / Q000235:genetics*; D003718:Denmark / Q000453:epidemiology; D004196:Disease Outbreaks; D016521:Electrophoresis, Gel, Pulsed-Field; D005516:Food Microbiology; D006801:Humans; D015994:Incidence; D008089:Listeria monocytogenes / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification; D008088:Listeriosis / Q000453:epidemiology* / Q000382:microbiology / Q000635:transmission; D017720:Molecular Epidemiology; D058885:Multilocus Sequence Typing; D010802:Phylogeny; D012703:Serotyping
chemical_list: D004269:DNA, Bacterial
keywords: Denmark; Listeria monocytogenes; bacteria; epidemiology; foodborne diseases; humans; listeriosis; molecular epidemiology; multilocus sequence typing; pulsed-field gel electrophoresis; zoonoses