Old Friends in New Places: Exploring the Role of Extraintestinal E. coli in Intestinal Disease and Foodborne Illness

The emergence of new antibiotic-resistant Escherichia coli pathotypes associated with human disease has led to an investigation in terms of the origins of these pathogens. According to the Centers for Disease Control and Prevention, unspecified agents are responsible for 38.4 million of the 48 million (80%) cases of foodborne illnesses each year in the United States. It is hypothesized that environmental E. coli not typically associated with the ability to cause disease in humans could potentially be responsible for some of these cases. In order for an environmental E. coli isolate to have the ability to cause foodborne illness, it must be able to utilize the same attachment and virulence mechanisms utilized by other human pathogenic E. coli. Recent research has shown that many avian pathogenic E. coli (APEC) isolated from poultry harbour attachment and virulence genes also currently found in human pathogenic E. coli isolates. Research also suggests that, in addition to the ability to cause gastrointestinal illnesses, APEC may also be an etiological agent of foodborne urinary tract infections (FUTIs). The purpose of this article was to evaluate the evidence pertaining to the ability of APEC to cause disease in humans, their potential for zoonotic transfer along with discussion on the types of illnesses that may be associated with these pathogens.