Epidemiology and Infection

Original Papers

Gastrointestinal infections

National patterns of Escherichia coli O157 infections, USA, 1996–2011

S. V. SODHAa1 c1, K. HEIMANa1a2, L. H. GOULDa1, R. BISHOPa1, M. IWAMOTOa1, D. L. SWERDLOWa1 and P. M. GRIFFINa1

a1 Centers for Disease Control and Prevention, Atlanta, GA, USA

a2 Atlanta Research and Education Foundation, Decatur, GA, USA


US public health laboratories began reporting Escherichia coli O157 isolates to CDC in 1996. We describe temporal and geographical patterns of isolates reported from 1996 to 2011 and demographics of persons whose specimens yielded isolates. We calculated annual E. coli O157 isolation rates/100 000 persons by patient's state of residence, county of residence, age, and sex using census data. The average annual isolation rate was 0·84. The average isolation rate in northern states (1·52) was higher than in southern states (0·43). Counties with ≥76% rural population had a lower isolation rate (0·67) than counties with ≤25%, 26–50%, and 51–75% rural populations (0·81, 0·92, and 0·81, respectively). The highest isolation rate (3·19) was in children aged 1–4 years. Infections were seasonal with 49% of isolates collected during July to September. Research into reasons for higher incidence in northern states and for seasonality could guide strategies to prevent illnesses.

(Received February 20 2013)

(Revised February 12 2014)

(Accepted March 19 2014)

(Online publication April 14 2014)

Key words

  • Escherichia coli O157;
  • haemolytic uraemic syndrome;
  • HUS;
  • Shiga toxin;
  • surveillance


c1 Author for correspondence: S. V. Sodha, MD, MPH, 1600 Clifton Road, MS A-04, Atlanta, GA 30333, USA. (Email: ssodha@cdc.gov)