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Show 288 Wendy Vu COMPARING THE VIRULENCE AND PREVALENCE OF SHIGA TOXIN-PRODUCING ESCHERICHIA COLI (STEC) O157 AND NON-O157 SEROGROUPS Wendy Vu (JoAnn Fenn, Julia Hall, Marilee O'Connor) Department of Pathology Utah Department of Health University of Utah honors college spring 2012 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 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 data-bases were analyzed for statistical significance on the basis of incidence, symptoms, and hospi-talization 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 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 hospitaliza-tion 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 public health response towards STEC infections. Julia Hall Marilee O'Connor |
