From the National Institute of Allergy and Infectious Diseases. Summary of a workshop on enteropathogenic Escherichia coli.

Abstract

A workshop on enteropathogenic Escherichia coli (EPEC) was held on September 20th and 21st 1982 at the National Institutes of Health. 50 investigators from 8 countries discussed the epidemiology diagnosis and pathogenesis of EPEC. By consensus of the workshop participants EPEC were defined as diarrheagenic E. coli belonging to serogroups epidemiologically incriminated as pathogens but whose pathogenic mechanisms have not been proven to be related either to heat labile enterotoxins (LT) or heat stable enterotoxins (ST) or to Shigella like invasiveness. EPEC adhere in a seemingly pathognomonic way to the intestinal epithelium. Due to the fact that investigation of EPEC had been minimal for 25 years the workshop was designed to provide new research directions. Participants reevaluated the role of EPEC as human diarrheal agents and identified existing and provocative possibilities for further investigation. Dr. Roy M. Robins-Browne provided a historical overview. Other participants discussed the worldwide magnitude of the problem diagnosis by serotyping mechanisms of pathogenesis mechanisms of pathogenesis animal models for EPEC adhesiveness tissue culture models for EPEC adhesiveness and mechanisms of pathogenesis. Investigators from several developing countries showed EPEC to be the cause of many epidemic and sporadic cases of the infantile diarrhea that occurs mostly in the summer. EPEC appears to have become a less frequent cause of epidemics in both Europe and America. A spectrum of clinical illnesses due to EPEC occurs but diarrhea caused by EPEC is often severe and protracted. Both in vitro and in vivo studies clearly identify a characteristic histopathologic lesion of enteroadhesiveness as manifested by both intestinal brush border destruction and epithelial cell plasma membrane pedestal formation at the sites of EPEC attachment as seen by electron microscopy. Newly developed animal model systems in pigs and rabbits should help elucidate pathogenic mechanisms of EPEC. Recommendations for future investigations include: reinvestigate the epidemiology of EPEC in the 1980s including their geographic distribution seasonability and relative importance in relation to other more recently discovered pathogens; learn the reasons for age related susceptibility to EPEC related diarrhea and why it presents almost exclusively as a disease of infants younger than 2 years of age; develop simplified accurate diagnostic methods including gene probes or antisera to unique pathogenic factors phenotypically expressed and resolve current confusion about the results of different EPEC toxin assays and the characterizations of the toxins themselves.