White Paper on Non-O157:H7 Shiga-toxin Producing E. coli from Meat and Non-Meat Sources

This white paper examined data on outbreaks caused by non-O157 STEC E. coli and for information on prevalence of these bacteria in meat, meat-producing animals, and other potential food and non-food vectors. The white paper also looked at data on the effectiveness of current interventions for controlling these foodborne pathogens and on recently devised methods for detecting these bacteria.

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Objectives

• Summarize available global epidemiological data on cases and outbreaks caused by non-O157:H7 Shiga-toxin producing E. coli (STEC) associated with meat and non-meat vehicles
• Evaluate the prevalence of non-O157:H7 STEC in meat and non-meat sources
• Evaluate the effectiveness of existing interventions for controlling non-O157:H7 STEC
• Assess methodologies for detecting non-O157:H7 STEC in animals, meat, other animal products, and other foods

Conclusions

Numerous serotypes of non-O157 STEC are present in ruminants and occasionally in other animals, produce, and drinking and surface water. Although many non-O157 STEC strains lack some important virulence genes and have a low pathogenic potential, there are other strains that cause sporadic cases of HUS and outbreaks with serious illness and fatalities. The true number of cases of illness caused by non-O157 STEC is certainly underestimated because many public health laboratories do not routinely test for these bacteria. Recently, new analytical methods have been developed to detect these bacteria in clinical, food, and environmental samples. Interventions used to control E. coli O157:H7 may also be effective against non-O157 STEC. However, there is a significant lack of knowledge about the distribution of virulent non-O157 serotypes in and on animals and their resistance to environmental stress. Many outbreaks caused by non-O157 STEC appear to involve person-to-person spread of bacteria and this is not well understood.

Deliverable

Shiga-toxin producing E. coli can cause devastating illness, particularly in the young, the elderly and the immunocompromised. Although the majority of STEC causing human illness in the U.S. are serotype O157:H7, it is estimated that non-O157 STEC strains cause 37,000 cases annually. Many non-O157 STEC serotypes are associated with cattle and other ruminants and outbreaks have been traced to contact with animals and consumption of meat, raw milk, water, and fresh produce. In one survey, non-O157 STEC were detected in 30% of samples of beef trim. These bacteria have also been detected in ground beef, ground lamb, buffalo meat, and in raw milk from cows, sheep and goats. Outbreaks can result in costly recalls of product as well as serious illness. This white paper brings together and integrates current information on non-O157 STEC and methods for their detection and points out gaps in knowledge about variations among pathogenic STEC serotypes. This information may aid in determining appropriate, effective control procedures and indicates where further research is needed.