Official reprint from UpToDate®
www.uptodate.com ©2017 UpToDate, Inc. and/or its affiliates. All Rights Reserved.

Pathogenic Escherichia coli

Christine A Wanke, MD
Section Editor
Stephen B Calderwood, MD
Deputy Editor
Allyson Bloom, MD


Escherichia coli are normal inhabitants of the human gastrointestinal tract and are among the bacterial species most frequently isolated from stool cultures. When E. coli strains acquire certain genetic material, they can become pathogenic. E. coli are among the most frequent bacterial causes of diarrhea and are classified by clinical syndrome they produce (table 1) [1].

The characteristics of diarrheal illness caused by enterotoxigenic E. coli (ETEC), enteropathogenic E. coli (EPEC), enterohemorrhagic E. coli (EHEC, also called Shiga toxin-producing E. coli or STEC), enteroinvasive E. coli (EIEC), and enteroaggregative E. coli (EAEC or EAggEc) will be reviewed here. EHEC is also discussed in greater detail separately. (See "Microbiology, pathogenesis, epidemiology, and prevention of enterohemorrhagic Escherichia coli (EHEC)" and "Clinical manifestations, diagnosis and treatment of enterohemorrhagic Escherichia coli (EHEC) infection".)


E. coli can be cultured readily from the stool under aerobic conditions. On selective media, such as MacConkey agar, E. coli usually appear as pink colonies, indicating that the organism ferments lactose (picture 1). Additional biochemical identification should also be performed, since up to 10 percent of E. coli do not ferment lactose or ferment lactose relatively slowly. The most useful biochemical identification test for E. coli is the indole test, which is positive in up to 99 percent of E. coli strains.

Pathogenic E. coli are not distinguishable from other strains or from each other by the appearance on culture plates or by the results of the usual biochemical tests. To determine whether the isolated strain is one of the pathogenic strains or merely a constituent of the normal flora, additional identification techniques must be employed, which are generally limited to research laboratory settings.

EHEC O157 is the only pathogenic strain that can be identified readily in the clinical laboratory [2]. Further testing on pathogenic E. coli isolates must be performed in a research or reference laboratory. This testing can include determining the serotype of the strain, performing biological assays (bioassays) that demonstrate strain virulence, and using genetic tools, such as DNA probing or polymerase chain reaction (PCR) amplification, to identify genetic material that encodes for specific virulence factors.

To continue reading this article, you must log in with your personal, hospital, or group practice subscription. For more information on subscription options, click below on the option that best describes you:

Subscribers log in here

Literature review current through: Nov 2017. | This topic last updated: Oct 08, 2017.
The content on the UpToDate website is not intended nor recommended as a substitute for medical advice, diagnosis, or treatment. Always seek the advice of your own physician or other qualified health care professional regarding any medical questions or conditions. The use of this website is governed by the UpToDate Terms of Use ©2017 UpToDate, Inc.
  1. Nataro JP, Kaper JB. Diarrheagenic Escherichia coli. Clin Microbiol Rev 1998; 11:142.
  2. March SB, Ratnam S. Sorbitol-MacConkey medium for detection of Escherichia coli O157:H7 associated with hemorrhagic colitis. J Clin Microbiol 1986; 23:869.
  3. Cassels FJ, Wolf MK. Colonization factors of diarrheagenic E. coli and their intestinal receptors. J Ind Microbiol 1995; 15:214.
  4. Black RE, Merson MH, Rowe B, et al. Enterotoxigenic Escherichia coli diarrhoea: acquired immunity and transmission in an endemic area. Bull World Health Organ 1981; 59:263.
  5. Black RE, Brown KH, Becker S, et al. Contamination of weaning foods and transmission of enterotoxigenic Escherichia coli diarrhoea in children in rural Bangladesh. Trans R Soc Trop Med Hyg 1982; 76:259.
  6. Beatty ME, Adcock PM, Smith SW, et al. Epidemic diarrhea due to enterotoxigenic Escherichia coli. Clin Infect Dis 2006; 42:329.
  7. Devasia RA, Jones TF, Ward J, et al. Endemically acquired foodborne outbreak of enterotoxin-producing Escherichia coli serotype O169:H41. Am J Med 2006; 119:168.e7.
  8. Yoder JS, Cesario S, Plotkin V, et al. Outbreak of enterotoxigenic Escherichia coli infection with an unusually long duration of illness. Clin Infect Dis 2006; 42:1513.
  9. Alves AM, Lásaro MO, Pyrrho AS, et al. Antibody response in mice immunized with a plasmid DNA encoding the colonization factor antigen I of enterotoxigenic Escherichia coli. FEMS Immunol Med Microbiol 1999; 23:321.
  10. Evans DG, Evans DJ Jr, Pierce NF. Differences in the response of rabbit small intestine to heat-labile and heat-stable enterotoxins of Escherichia coli. Infect Immun 1973; 7:873.
  11. Levine MM, Caplan ES, Waterman D, et al. Diarrhea caused by Escherichia coli that produce only heat-stable enterotoxin. Infect Immun 1977; 17:78.
  12. Sears CL, Kaper JB. Enteric bacterial toxins: mechanisms of action and linkage to intestinal secretion. Microbiol Rev 1996; 60:167.
  13. Dorsey FC, Fischer JF, Fleckenstein JM. Directed delivery of heat-labile enterotoxin by enterotoxigenic Escherichia coli. Cell Microbiol 2006; 8:1516.
  14. Moseley SL, Echeverria P, Seriwatana J, et al. Identification of enterotoxigenic Escherichia coli by colony hybridization using three enterotoxin gene probes. J Infect Dis 1982; 145:863.
  15. Begaud E, Germani Y. Detection of enterotoxigenic Escherichia coli in faecal specimens by acetylaminofluorene-labelled DNA probes. Res Microbiol 1992; 143:315.
  16. Rothbaum R, McAdams AJ, Giannella R, Partin JC. A clinicopathologic study of enterocyte-adherent Escherichia coli: a cause of protracted diarrhea in infants. Gastroenterology 1982; 83:441.
  17. Ulshen MH, Rollo JL. Pathogenesis of escherichia coli gastroenteritis in man--another mechanism. N Engl J Med 1980; 302:99.
  18. Donnenberg MS, Calderwood SB, Donohue-Rolfe A, et al. Construction and analysis of TnphoA mutants of enteropathogenic Escherichia coli unable to invade HEp-2 cells. Infect Immun 1990; 58:1565.
  19. Donnenberg MS, Tzipori S, McKee ML, et al. The role of the eae gene of enterohemorrhagic Escherichia coli in intimate attachment in vitro and in a porcine model. J Clin Invest 1993; 92:1418.
  20. Dytoc M, Fedorko L, Sherman PM. Signal transduction in human epithelial cells infected with attaching and effacing Escherichia coli in vitro. Gastroenterology 1994; 106:1150.
  21. Finlay BB, Rosenshine I, Donnenberg MS, Kaper JB. Cytoskeletal composition of attaching and effacing lesions associated with enteropathogenic Escherichia coli adherence to HeLa cells. Infect Immun 1992; 60:2541.
  22. Rabinowitz RP, Lai LC, Jarvis K, et al. Attaching and effacing of host cells by enteropathogenic Escherichia coli in the absence of detectable tyrosine kinase mediated signal transduction. Microb Pathog 1996; 21:157.
  23. Rosenshine I, Donnenberg MS, Kaper JB, Finlay BB. Signal transduction between enteropathogenic Escherichia coli (EPEC) and epithelial cells: EPEC induces tyrosine phosphorylation of host cell proteins to initiate cytoskeletal rearrangement and bacterial uptake. EMBO J 1992; 11:3551.
  24. McNamara BP, Koutsouris A, O'Connell CB, et al. Translocated EspF protein from enteropathogenic Escherichia coli disrupts host intestinal barrier function. J Clin Invest 2001; 107:621.
  25. Weflen AW, Alto NM, Hecht GA. Tight junctions and enteropathogenic E. coli. Ann N Y Acad Sci 2009; 1165:169.
  26. Gill RK, Borthakur A, Hodges K, et al. Mechanism underlying inhibition of intestinal apical Cl/OH exchange following infection with enteropathogenic E. coli. J Clin Invest 2007; 117:428.
  27. Ashokkumar B, Kumar JS, Hecht GA, Said HM. Enteropathogenic Escherichia coli inhibits intestinal vitamin B1 (thiamin) uptake: studies with human-derived intestinal epithelial Caco-2 cells. Am J Physiol Gastrointest Liver Physiol 2009; 297:G825.
  28. Scaletsky IC, Silva ML, Trabulsi LR. Distinctive patterns of adherence of enteropathogenic Escherichia coli to HeLa cells. Infect Immun 1984; 45:534.
  29. Baldini MM, Nataro JP, Kaper JB. Localization of a determinant for HEp-2 adherence by enteropathogenic Escherichia coli. Infect Immun 1986; 52:334.
  30. Knutton S, Baldwin T, Williams PH, McNeish AS. Actin accumulation at sites of bacterial adhesion to tissue culture cells: basis of a new diagnostic test for enteropathogenic and enterohemorrhagic Escherichia coli. Infect Immun 1989; 57:1290.
  31. Johnson KE, Thorpe CM, Sears CL. The emerging clinical importance of non-O157 Shiga toxin-producing Escherichia coli. Clin Infect Dis 2006; 43:1587.
  32. Boyce TG, Swerdlow DL, Griffin PM. Escherichia coli O157:H7 and the hemolytic-uremic syndrome. N Engl J Med 1995; 333:364.
  33. Karmali MA, Petric M, Lim C, et al. The association between idiopathic hemolytic uremic syndrome and infection by verotoxin-producing Escherichia coli. J Infect Dis 1985; 151:775.
  34. Tulloch EF Jr, Ryan KJ, Formal SB, Franklin FA. Invasive enteropathic Escherichia coli dysentery. An outbreak in 28 adults. Ann Intern Med 1973; 79:13.
  35. Nataro JP, Kaper JB, Robins-Browne R, et al. Patterns of adherence of diarrheagenic Escherichia coli to HEp-2 cells. Pediatr Infect Dis J 1987; 6:829.
  36. Vial PA, Robins-Browne R, Lior H, et al. Characterization of enteroadherent-aggregative Escherichia coli, a putative agent of diarrheal disease. J Infect Dis 1988; 158:70.
  37. Bhan MK, Khoshoo V, Sommerfelt H, et al. Enteroaggregative Escherichia coli and Salmonella associated with nondysenteric persistent diarrhea. Pediatr Infect Dis J 1989; 8:499.
  38. Bhan MK, Raj P, Levine MM, et al. Enteroaggregative Escherichia coli associated with persistent diarrhea in a cohort of rural children in India. J Infect Dis 1989; 159:1061.
  39. Bhatnagar S, Bhan MK, Sommerfelt H, et al. Enteroaggregative Escherichia coli may be a new pathogen causing acute and persistent diarrhea. Scand J Infect Dis 1993; 25:579.
  40. Cravioto A, Reyes RE, Ortega R, et al. Prospective study of diarrhoeal disease in a cohort of rural Mexican children: incidence and isolated pathogens during the first two years of life. Epidemiol Infect 1988; 101:123.
  41. Gunzburg ST, Chang BJ, Elliott SJ, et al. Diffuse and enteroaggregative patterns of adherence of enteric Escherichia coli isolated from aboriginal children from the Kimberley region of Western Australia. J Infect Dis 1993; 167:755.
  42. Henry FJ, Udoy AS, Wanke CA, Aziz KM. Epidemiology of persistent diarrhea and etiologic agents in Mirzapur, Bangladesh. Acta Paediatr Suppl 1992; 381:27.
  43. Wanke CA, Schorling JB, Barrett LJ, et al. Potential role of adherence traits of Escherichia coli in persistent diarrhea in an urban Brazilian slum. Pediatr Infect Dis J 1991; 10:746.
  44. Scotland SM, Smith HR, Cheasty T, et al. Use of gene probes and adhesion tests to characterise Escherichia coli belonging to enteropathogenic serogroups isolated in the United Kingdom. J Med Microbiol 1996; 44:438.
  45. Cobeljić M, Miljković-Selimović B, Paunović-Todosijević D, et al. Enteroaggregative Escherichia coli associated with an outbreak of diarrhoea in a neonatal nursery ward. Epidemiol Infect 1996; 117:11.
  46. Mayer HB, Wanke CA. Enteroaggregative Escherichia coli as a possible cause of diarrhea in an HIV-infected patient. N Engl J Med 1995; 332:273.
  47. Wanke CA, Mayer H, Weber R, et al. Enteroaggregative Escherichia coli as a potential cause of diarrheal disease in adults infected with human immunodeficiency virus. J Infect Dis 1998; 178:185.
  48. Nataro JP, Mai V, Johnson J, et al. Diarrheagenic Escherichia coli infection in Baltimore, Maryland, and New Haven, Connecticut. Clin Infect Dis 2006; 43:402.
  49. Huang DB, Nataro JP, DuPont HL, et al. Enteroaggregative Escherichia coli is a cause of acute diarrheal illness: a meta-analysis. Clin Infect Dis 2006; 43:556.
  50. Steiner TS, Lima AA, Nataro JP, Guerrant RL. Enteroaggregative Escherichia coli produce intestinal inflammation and growth impairment and cause interleukin-8 release from intestinal epithelial cells. J Infect Dis 1998; 177:88.
  51. Steiner TS, Nataro JP, Poteet-Smith CE, et al. Enteroaggregative Escherichia coli expresses a novel flagellin that causes IL-8 release from intestinal epithelial cells. J Clin Invest 2000; 105:1769.
  52. Nataro JP, Deng Y, Cookson S, et al. Heterogeneity of enteroaggregative Escherichia coli virulence demonstrated in volunteers. J Infect Dis 1995; 171:465.
  53. Sheikh J, Czeczulin JR, Harrington S, et al. A novel dispersin protein in enteroaggregative Escherichia coli. J Clin Invest 2002; 110:1329.
  54. Benjamin P, Federman M, Wanke CA. Characterization of an invasive phenotype associated with enteroaggregative Escherichia coli. Infect Immun 1995; 63:3417.
  55. Khan K, Konar M, Goyal A, Ghosh S. Enteroaggregative Escherichia coli infection induces IL-8 production via activation of mitogen-activated protein kinases and the transcription factors NF-kappaB and AP-1 in INT-407 cells. Mol Cell Biochem 2010; 337:17.
  56. Nataro JP. Enteroaggregative Escherichia coli pathogenesis. Curr Opin Gastroenterol 2005; 21:4.
  57. Jiang ZD, Greenberg D, Nataro JP, et al. Rate of occurrence and pathogenic effect of enteroaggregative Escherichia coli virulence factors in international travelers. J Clin Microbiol 2002; 40:4185.
  58. Boisen N, Struve C, Scheutz F, et al. New adhesin of enteroaggregative Escherichia coli related to the Afa/Dr/AAF family. Infect Immun 2008; 76:3281.
  59. Glandt M, Adachi JA, Mathewson JJ, et al. Enteroaggregative Escherichia coli as a cause of traveler's diarrhea: clinical response to ciprofloxacin. Clin Infect Dis 1999; 29:335.
  60. Wanke CA, Gerrior J, Blais V, et al. Successful treatment of diarrheal disease associated with enteroaggregative Escherichia coli in adults infected with human immunodeficiency virus. J Infect Dis 1998; 178:1369.