Non-O157 Shiga Toxin-Producing in Foods

Abstract

Non-O157 Shiga toxin-producing Escherichia coli (STEC) strains have been linked to outbreaks and sporadic cases of illness worldwide. Illnesses linked to STEC serotypes other than O157:H7 appear to be on the rise in the United States and worldwide, indicating that some of these organisms may be emerging pathogens. As more laboratories are testing for these organisms in clinical samples, more cases are uncovered. Some cases of non-O157 STEC illness appear to be as severe as cases associated with O157, although in general cases attributed to non-O157 are less severe. There is much variation in virulence potential within STEC serotypes, and many may not be pathogenic. Of more than 400 serotypes isolated, fewer than 10 serotypes cause the majority of STEC-related human illnesses. Various virulence factors are involved in non-O157 STEC pathogenicity; the combined presence of both eae and stx genes has been associated with enhanced virulence. A scientific definition of a pathogenic STEC has not yet been accepted. Several laboratories have attempted to develop detection and identification methods, and although substantial progress has been made, a practical method of STEC detection has yet to be validated. Worldwide, foods associated with non-O157 STEC illness include sausage, ice cream, milk, and lettuce, among others. Results from several studies suggest that control measures for O157 may be effective for non-O157 STEC. More research is needed to uncover unique characteristics and resistances of non-O157 STEC strains if they exist. The public health significance of non-O157 STEC and the implications for industry practices and regulatory actions are discussed.

Modeling gene associations for virulence classification of verocytotoxin-producing E. coli (VTEC) from patients and beef

“…An increasing number of VTEC O:H serotypes (more than 200) have been isolated from humans with gastrointestinal diseases. [11][12][13][14][15] However, the majority of severe infections are associated with a smaller group of serogroups, e.g., O157, O26, O103, O111 and O145, the so-called 'gang of five.' 16 Most disease outbreaks have been attributed to serotype O157:H7, even though non-O157 VTECs are more prevalent in animals and therefore likely to constitute a more common VTEC exposure among humans.…”

Serotypes and Virulence Profiles of Non-O157 Shiga Toxin-Producing Escherichia coli Isolates from Bovine Farms

“…STEC is common in ruminants and related foods (4,5,15,30,47). Clinical manifestations in humans range from hemorrhagic colitis (HC) to hemolytic uremic syndrome (HUS) and thrombocytopenic purpura (TTP) (3) and are directly related to the virulence genes present in the causative agent.…”

Survey of verotoxin-producing Escherichia coli and faecal coliforms in beef carcasses destined for export at slaughterhouses in Brazil

“…Non-O157 are also recognized as important pathogens involved with outbreaks of foodborne disease (European Food Safety Authority, 2009;Mathusa et al, 2010;Schaffzin et al, 2012). In the work of Fantelli & Stephan, 2001, seven shigatoxin producing E. coli were isolated from 400 samples (1.75%) of minced meat, and of the five distinct serotypes identified, none of the isolates belonged to O157: H7 serogroup.…”