title: Sodium chloride, potassium chloride, and virulence in Listeria monocytogenes.
abstract: Virulence, as determined in a mouse model, and the virulence factor activities of catalase, superoxide dismutase, and listeriolysin O were examined in a parental strain (10403S) and in a nonhemolytic mutant strain (DP-L224) of Listeria monocytogenes. The cells were propagated in media containing various concentrations of sodium chloride or potassium chloride. Strains 10403S and DP-L224 exhibited significant increases in catalase activity and listeriolysin O activity when grown in medium containing either salt at 428 mM. The superoxide dismutase activities for both strains increased when they were grown in medium containing either salt. The superoxide dismutase activity was significantly increased only when cells were propagated in medium containing no salt compared with that when they were propagated in medium containing either salt at 1,112 mM. In addition, the listeriolysin O activity was highest for cells propagated in medium containing KCl at 428 mM, while the activity was significantly less for cells propagated in medium containing NaCl at an equal concentration. Virulence was examined in mouse livers and spleens after intravenous infection, and approximate 50% lethal doses were determined after intragastric and intraperitoneal infection. Each method of infection indicated that listeriolysin O is required for virulence, while growth in salt-containing medium or the production of higher levels of catalase, superoxide dismutase, and listeriolysin O do not appear to enhance the virulence of L. monocytogenes.
authors.affiliation: Department of Food Science, University of Illinois, Urbana 61801.
authors.forename: E R
authors.initials: ER
authors.lastname: Myers
authors.forename: A W
authors.initials: AW
authors.lastname: Dallmier
authors.forename: S E
authors.initials: SE
authors.lastname: Martin
mesh_terms: D000818:Animals; D001427:Bacterial Toxins; D002374:Catalase / Q000187:drug effects / Q000378:metabolism; D006360:Heat-Shock Proteins / Q000187:drug effects / Q000378:metabolism; D006460:Hemolysin Proteins / Q000187:drug effects / Q000378:metabolism; D008089:Listeria monocytogenes / Q000187:drug effects / Q000201:enzymology / Q000472:pathogenicity*; D051379:Mice; D011189:Potassium Chloride / Q000494:pharmacology*; D012965:Sodium Chloride / Q000494:pharmacology*; D013482:Superoxide Dismutase / Q000187:drug effects / Q000378:metabolism; D014774:Virulence / Q000187:drug effects
chemical_list: D001427:Bacterial Toxins; D006360:Heat-Shock Proteins; D006460:Hemolysin Proteins; D012965:Sodium Chloride; D011189:Potassium Chloride; D002374:Catalase; D013482:Superoxide Dismutase; C038705:hlyA protein, Listeria monocytogenes