title: Ten-year trends and risk factors for non-O157 Shiga toxin-producing Escherichia coli found through Shiga toxin testing, Connecticut, 2000-2009.
abstract: BACKGROUND
  The epidemiology over time of non-O157 Shiga toxin-producing Escherichia coli (STEC) is unknown. Since 1999, increasing numbers of laboratories in Connecticut have been testing for ST rather than culturing for O157, enabling identification of non-O157 STEC.
  
  
  METHODS
  Beginning in 2000, Connecticut laboratories were required to submit ST-positive broths to the State Laboratory for isolation and typing of STEC. The ratio of non-O157:O157 from laboratories conducting ST testing was used to determine state-level estimates for non-O157 STEC. Patients with STEC were interviewed for exposure factors in the 7 days preceding illness. Incidence trends, clinical features, and epidemiology of non-O157 and O157 STEC infections were compared.
  
  
  RESULTS
  From 1 January 2000 through 31 December 2009, ST testing detected 392 (59%) of 663 reported STEC infections; 229 (58%) of the isolates were non-O157. The estimated incidence of STEC infection decreased by 34%. O157 and the top 4 non-O157 serogroups, O111, O103, O26, and O45, were a stable percentage of all STEC isolates over the 10-year period. Bloody diarrhea, hospitalization, and hemolytic uremic syndrome were more common in patients with O157 STEC than in patients with non-O157 STEC infection. Exposure risks of patients with non-O157 STEC infection differed from those of patients with O157 STEC infection primarily in international travel (15.3% vs 2.5%; P < .01). Non-O157 types differed from each other with respect to several epidemiologic and exposure features.
  
  
  CONCLUSIONS
  Both O157 and non-O157 STEC infection incidence decreased from 2000 through 2009. Although infection due to O157 is the most common and clinically severe STEC infection, it accounts for a minority of all clinically significant STEC infections. STEC appear to be a diverse group of organisms that have some differences as well as many epidemiologic and exposure features in common.
authors.affiliation: Emerging Infections Program, Division of Epidemiology of Microbial Diseases, Yale University School of Public Health, New Haven, Connecticut, USA. hadler-epi@att.net
authors.forename: James L
authors.initials: JL
authors.lastname: Hadler
authors.forename: Paula
authors.initials: P
authors.lastname: Clogher
authors.forename: Sharon
authors.initials: S
authors.lastname: Hurd
authors.forename: Quyen
authors.initials: Q
authors.lastname: Phan
authors.forename: Mona
authors.initials: M
authors.lastname: Mandour
authors.forename: Kelley
authors.initials: K
authors.lastname: Bemis
authors.forename: Ruthanne
authors.initials: R
authors.lastname: Marcus
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015373:Bacterial Typing Techniques; D002648:Child; D002675:Child, Preschool; D003237:Connecticut / Q000453:epidemiology; D004927:Escherichia coli Infections / Q000453:epidemiology* / Q000382:microbiology*; D005260:Female; D006801:Humans; D015994:Incidence; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D022621:Shiga Toxin / Q000032:analysis*; D054323:Shiga-Toxigenic Escherichia coli / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D055815:Young Adult
chemical_list: D022621:Shiga Toxin