title: Salt stress-induced invasiveness of major Listeria monocytogenes serotypes.
abstract: Of the 13 serotypes, 4b serotype strains are responsible for the majority of recorded invasive listeriosis outbreaks, although some recent listeriosis outbreaks have been attributed to strains of serotypes 1/2a and 1/2b. Virulence and response to osmotic stress in 41 Listeria monocytogenes strains representing serotypes 1/2a, 1/2b and 4b was investigated. It was found that serotype 4b and 1/2b strains exhibited highest invasion efficiency and formed largest plaques in HT-29 cell monolayer. Invasiveness in response to 10-min exposure to 0·3 mol l⁻¹ NaCl was the highest in serotype 4b strains. We demonstrated that 4b serotype L. monocytogenes strains not only have the greatest pathogenic potential but also are the most invasive in response to salt stress.
  
  
  CONCLUSIONS
  Listeria monocytogenes 4b serotype strains are responsible for the majority of recorded invasive listeriosis outbreaks. We showed that strains of serotype 4b are not only the most virulent L. monocytogenes strains but also have the best capacity to enhance their invasiveness in response to salt stress. Our results suggest possession of effective stress response mechanisms of 4b serotype strains, which may contribute to the high infection potential of this subpopulation.
authors.affiliation: Department of Food Hygiene and Consumer Health Protection, Wrocław University of Environmental and Life Sciences, Wrocław, Poland. ewa.walecka@up.wroc.pl
authors.forename: E
authors.initials: E
authors.lastname: Wałecka-Zacharska
authors.forename: K
authors.initials: K
authors.lastname: Kosek-Paszkowska
authors.forename: J
authors.initials: J
authors.lastname: Bania
authors.forename: R
authors.initials: R
authors.lastname: Karpíšková
authors.forename: T
authors.initials: T
authors.lastname: Stefaniak
mesh_terms: D001426:Bacterial Proteins / Q000378:metabolism; D019073:HT29 Cells; D006801:Humans; D008089:Listeria monocytogenes / Q000145:classification / Q000378:metabolism / Q000472:pathogenicity*; D008088:Listeriosis / Q000382:microbiology; D009997:Osmotic Pressure; D012703:Serotyping; D014774:Virulence
chemical_list: D001426:Bacterial Proteins; C069761:internalin protein, Bacteria