The epidemiology, detection and control of Escherichia coli O157

Numbers of cases of human infections caused by Escherichia coli O157 have i ncreased over the last decade in many countries. As well as the typical sym ptoms of gastrointestinal illness, the organism can cause more life-threate ning diseases such as haemorrhagic colitis and haemolytic uraemic syndrome (HUS). Although the incidence remains relatively low compared with the othe r foodborne pathogens such as Campylobacter and Salmonella, the mortality r ate associated with infection is much higher. Cattle are thought to be the main environmental source of this organism, and most cases have been associ ated with consumption of beef and beef products. However, other food vehicl es have been identified, such as apple cider and raw or unpasteurised milk and milk products. Cross-contamination has been shown to be an important fa ctor in outbreaks, which, together with the fact that the infectious dose i s low (as few as 10 cells), means that robust hygienic procedures are essen tial at all stages of the food chain to reduce risk of infection. Person-to -person spread is a common source of illness, and several laboratory-acquir ed cases have also occurred. Efficient detection, isolation and confirmatio n techniques are required to establish the reservoirs of this organism in t he environment and its spread into, and within, the food chain. This articl e reviews the epidemiology of E coli O157 and discusses detection and preve ntative methods, both developed and developing. (C) 1999 Society of Chemica l Industry.