[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [General pathology](https://durgical.com/en/general-pathology/) › [Gastrointestinal tract](https://durgical.com/en/general-pathology/areas/gi/) › Infectious enterocolitis # Infectious enterocolitis - Topic Germs cause diarrhoea either by making toxins that pump water out, or by invading and inflaming the bowel so blood and pus appear. Updated Nov 12, 2026 ## Key points - Watery, non-inflammatory: cholera, enterotoxigenic E. coli, norovirus, rotavirus, Giardia, Cryptosporidium. - Bloody, inflammatory: Shigella, Campylobacter, non-typhoidal Salmonella, EHEC, Entamoeba histolytica. - Acute infectious colitis: neutrophils in surface and crypt epithelium (cryptitis, crypt abscesses) with preserved crypt architecture. - Chronic changes (crypt distortion, basal plasmacytosis) suggest inflammatory bowel disease instead. - Post-infectious complications: reactive arthritis (HLA-B27), Guillain–Barré, haemolytic uraemic syndrome, post-infectious irritable bowel syndrome. ## What it is Infectious diarrhoea kills over a million people a year worldwide, half of them children under five. Pathogens vary with age, nutrition, immunity, geography and clean water. Mechanistically there are two broad groups: non-invasive, toxin-producing organisms that cause watery secretory diarrhoea with almost normal biopsies, and invasive or cytotoxic organisms that injure the mucosa and cause dysentery. Acute self-limited colitis keeps the crypt architecture, which separates it from inflammatory bowel disease. ## Main bacterial enteric pathogens | Organism | Usual source | Mechanism | Typical stool | Key complication | | --- | --- | --- | --- | --- | | [Vibrio cholerae](https://durgical.com/en/conditions/cholera/) | Contaminated water, shellfish | Toxin raises cAMP | Rice-water | Dehydration, shock | | [Campylobacter jejuni](https://durgical.com/en/conditions/bacterial-infectious-diarrhoea-and-dysentery/) | Undercooked poultry, raw milk | Motility, adherence, toxins, sometimes invasion | Watery, sometimes bloody | Guillain–Barré, reactive arthritis | | [Shigella](https://durgical.com/en/conditions/bacterial-infectious-diarrhoea-and-dysentery/) | Person to person, low dose | Invades via M cells; Shiga toxin (S. dysenteriae 1) | Bloody | Reactive arthritis, HUS | | [Non-typhoidal Salmonella](https://durgical.com/en/conditions/bacterial-infectious-diarrhoea-and-dysentery/) | Eggs, poultry, meat, milk | Invades epithelium and M cells | Watery or bloody | Bacteraemia in vulnerable hosts | | [Salmonella Typhi](https://durgical.com/en/conditions/typhoid-fever/) | Human carriers, water | Systemic spread via Peyer patches | Bloody diarrhoea or constipation | Perforation, carrier state | | Yersinia | Pork, raw milk, water | Invades Peyer patches | Variable | Pseudo-appendicitis, erythema nodosum | | E. coli (EHEC O157:H7) | Undercooked beef, produce | Shiga-like toxin | Bloody | Haemolytic uraemic syndrome | | [Clostridioides difficile](https://durgical.com/en/conditions/clostridioides-difficile-infection/) | Hospital, after antibiotics | Toxins A and B | Watery | Pseudomembranous colitis, toxic megacolon | ## Clinical notes - Oral rehydration is the life-saving treatment for most acute watery diarrhoea. - Acute diarrhoeal disease remains a leading cause of illness in Colombian children under five, where viral, bacterial and parasitic agents all contribute. ## Memory aid Toxins turn on the tap; invaders break the pipe. ## Test yourself Think of the answer, then tap the question to see it. ## Which histological feature separates acute infectious colitis from inflammatory bowel disease? Preserved crypt architecture; IBD shows crypt distortion and basal plasmacytosis from chronic injury. ## Which two organisms cause watery diarrhoea without invading the mucosa? Vibrio cholerae and enterotoxigenic E. coli (also norovirus, rotavirus, Giardia). ## Which post-infectious complication links Campylobacter with the nervous system? Guillain–Barré syndrome, through antibodies cross-reacting with nerve gangliosides. [Add to my cards (3)](https://durgical.app/estudiar/?add=/en/general-pathology/infectious-enterocolitis/) [More Pathology questions →](https://durgical.com/en/practice/?f=pathology) ## Elsewhere in DurgiPedia - [Water and electrolyte absorption and how diarrhea happens](https://durgical.com/en/physiology/water-and-electrolyte-absorption-and-how-diarrhea-happens/) - [Immunity to microbes: which arm defends against what](https://durgical.com/en/immunology/immunity-to-microbes-which-arm-defends-against-what/) ## Connections ## Related 7 - [Toxin-mediated diarrhoea: cholera and E. coli](https://durgical.com/en/general-pathology/toxin-mediated-diarrhoea-cholera-and-e-coli/) - [Invasive bacterial enterocolitis](https://durgical.com/en/general-pathology/invasive-bacterial-enterocolitis/) - [Typhoid fever: Peyer patch ulcers and typhoid nodules](https://durgical.com/en/general-pathology/typhoid-fever-peyer-patch-ulcers-and-typhoid-nodules/) - [Pseudomembranous colitis: C. difficile toxins and the volcano lesion](https://durgical.com/en/general-pathology/pseudomembranous-colitis-c-difficile-toxins-and-the-volcano-lesion/) - [Viral gastroenteritis: norovirus, rotavirus, adenovirus and SARS-CoV-2](https://durgical.com/en/general-pathology/viral-gastroenteritis-norovirus-rotavirus-adenovirus-and-sars-cov-2/) - [Intestinal protozoa: amoebic flask ulcers, Giardia and Cryptosporidium](https://durgical.com/en/general-pathology/intestinal-protozoa-amoebic-flask-ulcers-giardia-and-cryptosporidium/) - [Intestinal helminths](https://durgical.com/en/general-pathology/intestinal-helminths/) ## Related conditions 8 - [Acute (viral) gastroenteritis](https://durgical.com/en/conditions/acute-gastroenteritis/) - [Bacterial infectious diarrhoea and dysentery](https://durgical.com/en/conditions/bacterial-infectious-diarrhoea-and-dysentery/) - [Dehydration in children (acute diarrhoeal disease)](https://durgical.com/en/conditions/dehydration-in-children/) - [Cholera](https://durgical.com/en/conditions/cholera/) - [Typhoid (enteric) fever](https://durgical.com/en/conditions/typhoid-fever/) - [Clostridioides difficile infection](https://durgical.com/en/conditions/clostridioides-difficile-infection/) - [Giardiasis](https://durgical.com/en/conditions/giardiasis/) - [Intestinal amoebiasis (amoebic dysentery)](https://durgical.com/en/conditions/intestinal-amoebiasis/) [← All of general pathology](https://durgical.com/en/general-pathology/) Educational content on the mechanisms of disease; not a diagnostic or treatment guide and no substitute for a health professional's advice. No doses are given. Sources: [Diarrhoeal disease](https://www.who.int/news-room/fact-sheets/detail/diarrhoeal-disease) (World Health Organization, 2024); [Etiology of acute gastroenteritis among children less than 5 years of age in Bucaramanga, Colombia: A case-control study](https://europepmc.org/article/PMC/PMC7357789/) (PLoS neglected tropical diseases, 2020); [Viral Gastroenteritis](https://www.ncbi.nlm.nih.gov/books/NBK518995/) (StatPearls (NCBI Bookshelf), 2025). ## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake Representative model, for educational purposes only. --- Source: https://durgical.com/en/general-pathology/infectious-enterocolitis/ License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/general-pathology/infectious-enterocolitis/