Electron microscopic improvement in the study of diarrheagenic Escherichiacoli

In the versatile single species of Escherichia coli, the diarrheagenic grou p displays a remarkable array of virulence traits. These comprise microbial attachment, production of secretory endotoxins or cell-destroying cytotoxi ns, direct epithelial cell invasion, and localized effacement of the epithe lium. The knowledge of how enteric E. coli induce disease has become increa singly important in the world, because of new pathogen emergence, increasin g threats of drug resistance, and growing awareness of their importance in malnutrition and diarrhea. Numerous research programs have demonstrated var ious mechanisms of pathogenesis. We point out how some pathogens are able t o develop intercourse with their host through subversion of its cytoskeleto n and signaling processes without toxin secretion or heavy invasiveness. In that domain, the cellular biology of infected cells owes fundamental data to the electron microscopic approach. Combined with advances in microbiolog y and molecular biology, this approach may provide answers to many unanswer ed questions. Microsc. Res. Tech. 49:383-393, 2000. (C) 2000 Wiley-Liss, In c.