title: Listeria monocytogenes infection from foods prepared in a commercial establishment: a case-control study of potential sources of sporadic illness in the United States.
abstract: BACKGROUND
  Listeria monocytogenes has been estimated to cause >2500 illnesses and 500 deaths annually in the United States. Efforts to reduce foodborne listeriosis have focused on foods frequently implicated in outbreaks. Potential sources for L. monocytogenes infection not associated with outbreaks remain poorly understood.
  
  
  METHODS
  The Foodborne Diseases Active Surveillance Network conducts surveillance for culture-confirmed listeriosis at clinical laboratories in 9 states. After excluding outbreak-associated cases, we attempted to enroll eligible case patients with L. monocytogenes infection in a case-control study from 2000 through 2003. Control subjects were recruited through health care providers and were matched to case patients by state, age, and immunosuppression status. Data were collected about exposures occurring in the 4 weeks before specimen collection from the case patients.
  
  
  RESULTS
  Of the 249 case patients with L. monocytogenes infection, only 12 (5%) had cases that were associated with outbreaks; 6 other patients were ineligible for other reasons. Of 231 eligible case patients, 169 (73%) were enrolled in the study. We classified 28 case patients as having pregnancy-associated cases. We enrolled 376 control subjects. In multivariable analysis, L. monocytogenes infection was associated with eating melons at a commercial establishment (odds ratio, 2.6; 95% confidence interval, 1.4-5.0) and eating hummus prepared in a commercial establishment (odds ratio, 5.7; 95% confidence interval, 1.7-19.1).
  
  
  CONCLUSIONS
  Most cases of L. monocytogenes infection were not associated with outbreaks. Reducing the burden of foodborne listeriosis may require interventions directed at retail environments and at foods, such as melons and hummus, that are not commonly recognized as high risk. Because of the severity of listeriosis, pregnant women and other persons at risk may wish to avoid eating these newly implicated foods.
authors.affiliation: Epidemic Intelligence Service, Centers for Disease Control and Prevention, Atlanta, GA 30333, USA.
authors.forename: Jay K
authors.initials: JK
authors.lastname: Varma
authors.forename: Michael C
authors.initials: MC
authors.lastname: Samuel
authors.forename: Ruthanne
authors.initials: R
authors.lastname: Marcus
authors.forename: Robert M
authors.initials: RM
authors.lastname: Hoekstra
authors.forename: Carlota
authors.initials: C
authors.lastname: Medus
authors.forename: Suzanne
authors.initials: S
authors.lastname: Segler
authors.forename: Bridget J
authors.initials: BJ
authors.lastname: Anderson
authors.forename: Timothy F
authors.initials: TF
authors.lastname: Jones
authors.forename: Beletshachew
authors.initials: B
authors.lastname: Shiferaw
authors.forename: Nicole
authors.initials: N
authors.lastname: Haubert
authors.forename: Melanie
authors.initials: M
authors.lastname: Megginson
authors.forename: Patrick V
authors.initials: PV
authors.lastname: McCarthy
authors.forename: Lewis
authors.initials: L
authors.lastname: Graves
authors.forename: Thomas Van
authors.initials: TV
authors.lastname: Gilder
authors.forename: Frederick J
authors.initials: FJ
authors.lastname: Angulo
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D005260:Female; D005502:Food; D005506:Food Contamination / Q000706:statistics & numerical data*; D005511:Food Handling; D005519:Food Preservation; D005517:Foodborne Diseases / Q000453:epidemiology / Q000382:microbiology; D006801:Humans; D015994:Incidence; D007223:Infant; D008089:Listeria monocytogenes / Q000302:isolation & purification*; D008088:Listeriosis / Q000175:diagnosis / Q000453:epidemiology*; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011159:Population Surveillance; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious / Q000453:epidemiology* / Q000382:microbiology; D012016:Reference Values; D012307:Risk Factors; D017678:Sex Distribution; D015996:Survival Rate; D014481:United States / Q000453:epidemiology