Outbreak of enterotoxigenic Escherichia coli infection with an unusually long duration of illness.

Background: Enterotoxigenic Escherichia coli (ETEC) is an emerging cause of foodborne outbreaks of infection in the United States, yet its epidemiology is not completely understood.

Methods: In September 2004, we investigated an outbreak of infection due to ETEC at an Illinois corporation following a meal served to approximately 700 employees. Clinical samples were negative for enteric pathogens and were tested for ETEC using stool culture and polymerase chain reaction (PCR).