2005 - Escherichia Coli O157:H7

Table 1. E. coli O157:H7 Cases by Race and Sex, Indiana, 2005

  2005 2001-2005
Cases Rate* Cases
Total 77 1.23 403
   White 51 0.92 281
   Black 2 0.36 16
   Other 1 0.61 5
   Not Reported 23 - 101
   Male 37 1.20 174
   Female 40 1.26 229
   Not Reported 0 - 0

Escherichia coli O157:H7 infection is a bacterial disease usually transmitted through raw or undercooked foods of animal origin or foods cross-contaminated by animal products or feces. It has commonly been associated with raw or undercooked hamburger, unwashed produce, and unpasteurized juices. Outbreaks have also been attributed to swimming in or drinking untreated surface water. The infection can also be transmitted person to person and is a special concern in the daycare setting. Rarely, patients can develop hemolytic uremic syndrome (HUS) as a result of E. coli O157:H7 infection. Symptoms of this disorder include kidney dysfunction, hemolytic anemia, and platelet loss; HUS can be fatal. Populations at most risk include young children, the elderly, and those with weakened immune systems. Approximately 2-7 percent of E. coli O157:H7 cases will develop HUS.

In 2005, 77 cases of E. coli O157:H7 infection were reported in Indiana, for a rate of 1.23 cases per 100,000 population. Figure 1 shows the number of reported cases per year for 2001-2005. Incidence of disease was greatest during the late spring, summer, and early fall months. Figure 2 shows the number of cases per month in Indiana for 2005. As shown in Figure 3, age-specific rates were highest among preschoolers aged 1-4 years (4.65), followed by infants less than 1 year of age (2.32), and adults aged 60-69 years (2.25). Females (1.26) were slightly more likely to be reported than males (1.20). The rate for whites was higher (0.92) than that for other races (0.61) and blacks (0.36); however, 23 cases (30%) did not report race data.

Although 37 counties reported cases of E. coli O157:H7, only Allen (12), Marion (8), and Madison (6) had 5 or more cases (Figure 4).

There were two reported outbreaks of E. coli O157:H7 infection in Indiana in 2005. The first outbreak occurred at a daycare facility in Allen County. Eleven children and one contact of a daycare attendee tested positive for E. coli O157:H7. The only consistent common exposure among the cases was an association with the daycare center. No foods were implicated as the source of the outbreak. Cross-contamination may have been a contributing factor in the cause of this outbreak by the close person-to-person contact among children sharing toys and the use of cloth towels for hand drying. The daycare staff members were provided with recommendations for preventing future outbreaks including proper hand-washing techniques and excluding ill staff members.

The second outbreak of E. coli O157:H7 occurred in 10 individuals after eating at an American Legion Post in St. Joseph County. At least 150 people attended a Mother’s Day brunch at the American Legion Post. The St. Joseph County Health Department (SJCHD) Foods Division was notified that at least seven people were ill after consuming the suspect meal. Temperature control violations contributed to the outbreak. None of the employees reported being ill while preparing the food. Food samples were collected and submitted to the Indiana State Department of Health Laboratory for analysis. The samples tested positive for E. coli O157:H7. The SJCHD advised the restaurant’s management of proper food preparation techniques and permissible food sources.

Of the 77 confirmed E. coli O157:H7 cases reported in 2005, 1 case reported developing HUS.

It is recommended that all clinical laboratories routinely screen all stool specimens for sorbitol-negative E. coli strains. Lack of sorbitol fermentation in E. coli bacteria is a biochemical marker for the O157:H7 serotype. The ISDH requests that clinical laboratories submit all E. coli O157:H7 or sorbitol-negative E. coli isolates to the ISDH Laboratories for free confirmation and subtyping services.

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