title: Role of foods in sporadic listeriosis. II. Microbiologic and epidemiologic investigation. The Listeria Study Group.
abstract: OBJECTIVE
  To evaluate the role of foods in sporadic listeriosis.
  
  
  METHODS
  Microbiologic survey of foods collected from refrigerators of patients with listeriosis identified through active laboratory-based surveillance. Patient and food Listeria monocytogenes isolates were subtyped to identify foods contaminated with the same strain of L monocytogenes that caused illness in the patient; samples of these foods were obtained from the retail source.
  
  
  METHODS
  Multistate population-based study conducted between 1988 and 1990.
  
  
  RESULTS
  Listeria monocytogenes grew from at least one food specimen in the refrigerators of 79 (64%) of 123 listeriosis patients; 11% of more than 2000 food specimens collected in the study contained L monocytogenes. Twenty-six (33%) of 79 refrigerators with foods that grew L monocytogenes contained at least one food isolate of the same strain as that in the corresponding patient, a frequency much higher than would be expected by chance (P less than .001). Multivariate analysis showed that of the food specimens that grew L monocytogenes, foods that were ready-to-eat, foods that grew L monocytogenes by a direct-plating method (a measure of the level of contamination), and foods that contained serotype 4b isolates were independently associated with an increased likelihood of containing the patient-matching strain.
  
  
  CONCLUSIONS
  We identified specific food and L monocytogenes isolate characteristics--ready-to-eat foods, foods containing higher concentrations of L monocytogenes, and foods containing serotype 4b--which were associated with disease-causing strains. These results can provide guidance to industry and regulatory agencies in developing strategies to prevent listeriosis.
authors.affiliation: Meningitis and Special Pathogens Branch, Centers for Disease Control, Atlanta, Ga 30333.
authors.forename: R W
authors.initials: RW
authors.lastname: Pinner
authors.forename: A
authors.initials: A
authors.lastname: Schuchat
authors.forename: B
authors.initials: B
authors.lastname: Swaminathan
authors.forename: P S
authors.initials: PS
authors.lastname: Hayes
authors.forename: K A
authors.initials: KA
authors.lastname: Deaver
authors.forename: R E
authors.initials: RE
authors.lastname: Weaver
authors.forename: B D
authors.initials: BD
authors.lastname: Plikaytis
authors.forename: M
authors.initials: M
authors.lastname: Reeves
authors.forename: C V
authors.initials: CV
authors.lastname: Broome
authors.forename: J D
authors.initials: JD
authors.lastname: Wenger
mesh_terms: D005502:Food; D005516:Food Microbiology; D006801:Humans; D008089:Listeria monocytogenes / Q000302:isolation & purification*; D008088:Listeriosis / Q000453:epidemiology / Q000382:microbiology*; D014481:United States / Q000453:epidemiology