Escherichia coli O157:H7 diarrhea in a nursing home: clinical, epidemiological, and pathological findings.

In September 1984, an outbreak of Escherichia coli O157:H7 infection occurred in a nursing home. It was the first recognized outbreak of this organism in the United States since 1982, when two outbreaks led to its recognition as a pathogen. Thirty-four of 101 residents developed a diarrheal illness; 14 were hospitalized with a severe illness characterized by crampy abdominal pain, marked abdominal distention, and grossly bloody diarrhea, and four died. The spectrum of illness associated with the infection was broad and included the following: asymptomatic infection, nonbloody diarrhea, hemorrhagic colitis, hemolytic uremic syndrome, and death. Clinical, radiographic, and postmortem pathological findings suggested involvement of the cecum and right colon. No evidence of response to antimicrobial agents could be documented, and antidiarrheal agents may have aggravated the disease. This investigation implicated hamburger as the vehicle transmission. Seventeen of 19 residents with hemorrhagic colitis, but only 28 of 67 healthy residents, had eaten hamburger on 13 September (P less than .001, Fisher's two-tailed exact test; relative risk [RR] = 7.7). Infection with E. coli O157:H7 can cause a wide range of manifestations. In the elderly these can be particularly severe and may resemble ischemic colitis.