Description |
Shiga toxin-producing Escherichia coli (STEC) are bacteria known to cause human illness. The Center for Disease Control and Prevention estimates that 265,000 STEC infections occur in the United States (U.S.) annually; symptoms range from mild diarrhea to life-threatening hemolytic uremic syndrome. STEC transmission occurs fecal-orally and may be foodborne; waterborne; or through direct contact with infected persons, animals, or surfaces. Serogroup O157 is the most common STEC strain found in the U.S. and is historically understood as more virulent than non-O157 strains. However, with improved testing methods, non-O157 STEC are a rising concern. Confirmed cases of STEC O157 and non-O157 infections from Utah Department of Health databases were analyzed for statistical significance on the basis of incidence, symptoms, and hospitalization status. From 2005 to 2011, there were 633 confirmed STEC cases in the state of Utah. STEC O157 strains accounted for 54% of these infections, and multiple non-O157 serogroups accounted for the remaining 46%. Counts of non-O157 STEC cases increased during this time period-rising from 25 cases in 2005 to 73 cases in 2011. This may reflect a true increase or may be the result of improved detection methods. The most common clinical findings in all serotypes, O157 and non-O157 respectively, were non-bloody diarrhea (96% : 97%), abdominal pain (88% : 87%), and bloody diarrhea (80% : 67%). STEC O157 cases were associated with slightly higher hospitalization rates than non-O157 strains (31% : 21%). This study provides baseline epidemiological data that may contribute to a more comprehensive understanding among the various STEC serogroups. Overall, findings suggest that STEC O157 and non-O157 strains may cause a similar degree of clinical severity. This demonstrates the emerging significance of non-O157 strains and may influence the medical community and public health response towards STEC infections. |