An outbreak of Escherichia coli O157:H7 infections associated with leaf lettuce consumption

J Infect Dis. 1998 Jun;177(6):1588-93. doi: 10.1086/515323.

Abstract

In July 1995, 40 Montana residents were identified with laboratory-confirmed Escherichia coli O157:H7 infection; 52 residents had bloody diarrhea without laboratory confirmation. The median age of those with laboratory-confirmed cases was 42 years (range, 4- 86); 58% were female. Thirteen patients were hospitalized, and 1 developed hemolytic-uremic syndrome. A case-control study showed that 19 (70%) of 27 patients but only 8 (17%) of 46 controls reported eating purchased (not home-grown) leaf lettuce before illness (matched odds ratio, 25.3; 95% confidence interval, 3.9-1065.6). Pulsed-field gel electrophoresis identified a common strain among 22 of 23 isolates tested. Implicated lettuce was traced to two sources: a local Montana farm and six farms in Washington State that shipped under the same label. This outbreak highlights the increasing importance of fresh produce as a vehicle in foodborne illness. Sanitary growing and handling procedures are necessary to prevent these infections.

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Animals
  • Case-Control Studies
  • Cattle
  • Child
  • Child, Preschool
  • Disease Outbreaks*
  • Epidemiologic Methods
  • Escherichia coli Infections / epidemiology*
  • Escherichia coli Infections / etiology*
  • Escherichia coli Infections / physiopathology
  • Escherichia coli O157*
  • Female
  • Humans
  • Lettuce / poisoning*
  • Lipopolysaccharides / blood
  • Lipopolysaccharides / immunology
  • Male
  • Middle Aged
  • Plant Leaves
  • Sheep

Substances

  • Lipopolysaccharides