Last updated date: 10-Apr-2023

Originally Written in English

Various Colon Infections


    The colon, commonly known as the large intestine, is a digestive tract part. The stomach and small intestine digest and absorb the food that you ingest. The colon aids in the reclaiming of bodily fluids and the absorption of nutrients from leftover meals.

    Mucosa, the colon's deepest layer, comes into close touch with food. The mucosa assists in the absorption of water and electrolytes from meals into the bloodstream. Undigested food condenses into waste products when the water is removed. These substances are subsequently passed via the rectum and expelled as feces.

    Colitis is a disease in which the lining of the colon is inflamed, either acutely or chronically. It is becoming more frequent across the world. Infections, autoimmunity, inflammatory bowel disease, ischemic colitis, medications, and radiation exposure are all possible causes of colitis.

    Infection is the most prevalent cause of colitis, and it has become a major public health problem as a result. In this post, we'll look at colon infections, including the most common causes, how to identify them, and the treatments that are available, as well as how to avoid them.


    What is Infectious Colitis?

    Bowel infections, also known as gastrointestinal infections, are caused by microbes in the gut (gastroenteritis).

    Colon infection, often known as infectious colitis, is a wide term. The majority of patients presenting with acute diarrhea are caused by bacterial, viral, or parasite infections of the large intestine. For a diverse range of bacterial infections, the colon is a common location of infection.



    • Bacterial colitis is responsible for up to 47% of all cases of acute diarrhea.
    • Campylobacter jejuni is the most common bacterial cause of diarrhea, with a frequency of 25 to 30 per 100,000 people globally.
    • Yersinia enterocolitica colitis is most prevalent in young children during the winter. In the United States, one case per 100,000 people is reported per year.

    After malaria, Chagas disease, and leishmaniasis, Amebiasis is the second greatest cause of protozoan infection-related mortality.


    What are the Risk Factors of Colon Infection?

    • Age: Because their immune systems are still growing, children and babies are prone to colon infections. Furthermore, as people age, their immune systems grow less effective, making them more susceptible to colon infections. 
    • Compromised immunity: Reduced immunity creates a breeding environment for germs and parasites in the intestines. If a person's immune system is weakened, opportunistic colon infections are more frequent. 
    • Underlying conditions: Underlying intestinal conditions such as inflammatory bowel disorder (IBD), ischaemic colitis, and colorectal cancer can damage the colon lining. It can leave the colon vulnerable to infections.
    • Lower stomach acid content: The stomach's acid content aids in the destruction of pathogenic microorganisms. Proton pump inhibitors, for example, help to decrease stomach acidity. Excessive usage of these medicines might deplete the body's natural protective layer. The germs have the ability to move through the digestive tract and infect the gut and colon.

    People commonly get infected by:

    1. Ingesting or drinking contaminated food or water (often called food poisoning)
    2. Contact with sick individuals or contaminated things like flatware, faucets, toys, or nappies

    The fecal-oral pathway is typically used to transmit colon illnesses. Pathogens (disease-causing organisms) in the feces can infect the food you consume if you don't properly sanitize and maintain personal hygiene.


    What are the Symptoms of Colon Infection?

    Symptoms of Colon Infection

    Although the symptoms may vary based on the cause of infection, they typically include:

    • Watery diarrhea
    • Fever
    • Abdominal cramps
    • Pain and tenderness in the region of infection
    • Nausea
    • Vomiting
    • Tenesmus,
    • Urgency

    Severe infection may also present with:

    • Diarrhea for more than ten to fifteen times a day
    • Dehydration
    • Blood or pus in the stool
    • Kidney failure

    What are the Causes of Infection of Colon?

    Common pathogens responsible for colon infection include viruses, bacteria, and parasites.


    A. Bacterial causes: Following bacteria can commonly cause colon infection:

    • Campylobacter jejuni
    • Clostridium difficile
    • Escherichia coli
    • Shigella
    • Salmonella
    • Escherichia coli
    • Yersinia enterocolitica


    1. Campylobacter jejuni

    • Campylobacter jejuni infection is caused by ingesting contaminated food or drink. Several variables impact infection, including the amount of bacteria consumed, the pathogenicity of organisms, and the host's immunity. The incubation period is typically 2 to 4 days.
    • C jejuni multiplies in the bile before invading the epithelial layers and traveling to the lamina propria, causing a widespread, bloody, and edematous enteritis.


    2. Clostridium difficile

    • The bacterium Clostridium difficile can induce an opportunistic colon infection called pseudomembranous colitis. These bacteria usually cohabit with the colon's other bacterial fauna. Antibiotic treatment, such as cephalosporin clindamycin, carbapenems, trimethoprim, and fluoroquinolones, alters natural microflora, and the illness develops as a result.
    • This allows Clostridium difficile to colonize the gut and produce toxins as a result of overgrowth and colonization. Clostridium difficile produces a toxin that causes pseudomembranous colitis.
    • Patients with inflammatory bowel illness, particularly ulcerative colitis, are more susceptible to getting Clostridium difficile inection.


    3. Escherichia. coli

    • The most common routes of  E. coli infection include the fecal-oral route, animal hosts, and ingestion of contaminated food and drink.
    • Strains of E. coli that cause gastroenteritis in humans can be grouped into six categories:
    1. Enteroaggregative E. coli (EAEC)
    2. Enterohemorrhagic E. coli  (EHEC)
    3. Enteroinvasive E. coli (EIEC),
    4. Enteropathogenic E. coli (EPEC)
    5. Enterotoxigenic E. coli (ETEC)
    6. Diffusely adherent E. coli (DAEC)


    • Enterotoxigenic E. coli is the leading cause of traveler’s diarrhea.
    • Enterohemorrhagic E. coli has two major serotypes : E. coli O157: H7 and non-O157: H7; Cows are the natural reservoirs of both serotypes. Therefore, the illness is linked to the intake of undercooked meat, contaminated milk, or vegetables. They induce bloody diarrhea and generate Shiga-like toxins, resulting in symptoms similar to Shigella dysenteriae infection.
    • Enterotoxigenic E. coli and enteroaggregative E. coli are two of these subgroups that produce non-bloody diarrhea. Both generate enterotoxins that stimulate chloride and water output while inhibiting absorption.
    • Both enteropathogenic E. coli and enteroinvasive E. coli do not produce toxins. they invade enterocytes and cause self-limited colitis and is responsible for outbreaks particularly in children less than two years of age.


    4. Shigellosis

    • Shigella is a frequent water source contamination. Shigella may infect the large intestine with as little as 200 organisms, and around 1 million organisms must infect the large intestine to produce campylobacteriosis and salmonellosis. Shigella seldom gets into the bloodstream, which is a good thing.
    • Shigellosis is mainly a disease of children between the ages of 1 and 4 years.
    • Shigella is extremely resistant to stomach acid elimination. Around 50 Shigella species can be divided into four serologic categories. In the United States, S sonnei is the most often isolated cause of shigellosis.
    • Shigellosis is spread largely through the feces-oral route. This bacterial illness is disseminated via contaminated drinking water and person-to-person transfer.
    • The first nonspecific signs of shigellosis appear after a 36–72 hour incubation period, and include a temperature (39°C) and cramping stomach discomfort. After 48 hours, watery diarrhea generally occurs, followed by dysentery (bloody mucous-containing small volume stools and tenesmus) 2 days later.
    • Tenderness in the abdomen is generally widespread. Hyperemia, many tiny bleeding sites, lack of transverse mucosal folds, and thick, purulent mucous discharges are all seen on sigmoidoscopy. There is tenesmus, the feces are bloody, mucoid, and low in volume. Fluid and electrolyte loss may be relatively significant, particularly in pediatric and geriatric populations.


    5. Salmonellosis

    • Salmonella may cause illness in humans in a variety of ways. Some strains, such as S enterica, infiltrate the tissues of the gut but do not spread to other organs of the body through the circulation. Salmonella nontyphoidal strains are another name for these bacteria. Salmonella enterica causes enteritis, the most frequent Salmonella infection.
    • Other Salmonella strains, such as Salmonella Typhi, Salmonella Paratyphi A, Salmonella Schottmuelleri, and Salmonella Hirschfeldii, can infiltrate the tissues of the gut and spread to other regions of the body via the bloodstream. 


    B. Viral causes: Viruses causing colon infections include:

    1. Norovirus
    2. Rotavirus
    3. Adenovirus
    4. Cytomegalovirus


    • Infants and young children are vulnerable to viral colitis such as Norovirus, Rotavirus and Adenovirus. Nausea, vomiting, watery diarrhea, and stomach discomfort are common symptoms among those who are affected.
    • Hematochezia and diarrhea, on the other hand, are the most common symptoms CMV infection. Clinically, it's difficult to tell the difference between ulcerative colitis and CMV colitis.


    C. Parasitic causes (Entamoeba histolytica):

    • The Entamoeba histolytica protozoan parasite, which may infect the colonic mucosa and cause colitis, is the most frequent parasite that causes a colon infection.
    • The only parasite that causes dysentery is Entamoeba histolytica, which is rare in the United States. It can, however, infect tissues adjacent to the colon and cause illnesses all over the world. With a higher prevalence in underdeveloped countries. Male homosexuals, new immigrants, and institutionalized groups are all susceptible to E.histolytica infection (e.g., prison inmates).
    • Amebiasis symptoms include diarrhea, abdominal cramps, nausea and vomiting, and tenesmus after a 1–5 day incubation period. Feces can be watery, and in dysentery, feces are usually watery, with mucus and blood.
    • Amebiasis is spread by feces-contaminated drinking water and foods, but it can also be spread through sexual intercourse or direct touch with feces-contaminated hands or items.



    Sexually transmitted infections that affect the rectum should be taken into account throughout the evaluation. Neisseria gonorrhoeae, Chlamydia trachomatis, Herpes simplex, and Treponema pallidum are some of the illnesses that might affect HIV patients and men who have sex with males.


    How is Colon Infection Diagnosed?

    Colon Infection Diagnosed

    • In order to establish the diagnosis, a detailed medical history and identification of specific related risks are required.
    • Microbiological tests and cultures for bacterial and parasite infestations should be the primary investigations since colonic infection is a frequent etiology of colitis and can generate clinical presentations that are indistinguishable from inflammatory bowel disease.
    • Patient's age, hemodynamic changes, nocturnal diarrheas, tenesmus, urgency, weight loss, comorbidities, history of heart failure, arrhythmias, autoimmune disorders, detailed history of patient's medication, signs suggestive of toxic megacolon, and anemia are all red flags that should be looked for by the examining doctor.
    • A complete blood count, ESR, CRP, arterial blood gases, activated partial thromboplastin time, serum albumin, total protein, blood urea, creatinine, electrolytes, and purified protein derivative should all be requested as part of the laboratory workup.
    • Your doctor may recommend undergoing a stool test. A culture of the stools helps to identify the pathogen responsible for causing an infection in the intestines. stool culture helps in the diagnosis of less than 50% of patients presenting with bacterial colitis,
    • In cases with severe symptoms, the doctor may also prescribe a colonoscopy. The colon examination helps the doctor to look at the infected area of the colon.
    • The presence of E histolytica in feces or tissues taken from lesions confirms the diagnosis of amebiasis. It's typical to have leukocytosis without eosinophilia. Cysts in feces are detected using ELISA tests.
    • A CT scan or an abdominal X-ray may be recommended if the doctor detects any complication. It aids in the detection of problems such as thickening of the colon wall, distension of the colon, and bowel perforation.
    • CT scans of the abdomen were recently utilized to distinguish inflammatory bowel disease from acute colitis caused by bacterial infection.

    The four signs described to diagnose bacterial colitis are:

    1. Continuous distribution
    2. Empty colon
    3. Absence of fat stranding
    4. Absence of enlarged lymph nodes


    What are the Treatment Options for Colon Infection?

    Not all infectious colitis requires antibiotic therapy ,it Depend on the pathogen responsible for the colon infection, the doctor will prescribe antibiotics. Antibiotics are, however, ineffective against viral causes of the infectious condition. 

    • Antibiotic treatment is required for individuals with AIDS, cancer, transplantation, prosthetic implants, valvular heart disease, or advanced age.
    • Patients with mild to moderate C. jejuni or Salmonella infections do not need antibiotic therapy because the infection is self-limited.
    • For cases of C. difficile to C. difficile to C. d The recommended therapy for Clostridium difficile infection is metronidazole. If you have a severe case of C. Oral vancomycin is indicated for C. difficile infection. Oral vancomycin plus intravenous metronidazole is suggested in difficult situations.
    1. Treatment with quinolinic acid antibiotics is reserved for patients with dysentery and high fever suggestive of bacteremia.
    2. Antiviral medicines may not be necessary for the majority of individuals with CMV colitis who are immunocompetent. Valganciclovir is used to treat cytomegalovirus colitis in immunocompromised patients.


    • In patients, particularly children, with enterohemorrhagic E. coli (E. coli O157: 7H and non-O157: H7), Antibiotics are not recommended for treating infection because killing the bacteria might result in more Shigella toxins being released, increasing the risk of hemolytic uremic syndrome.
    • Shigellosis is typically a self-limiting disease; however, therapy with trimethoprim-sulfamethoxazole or ciprofloxacin is frequently advised to reduce the duration of the sickness and prevent person-to-person transmission. In extreme instances, fluid and electrolyte replacement is required. Peristalsis-inhibiting antidiarrheal drugs are not recommended.
    • E. histolytica treatment is recommended even in asymptomatic individuals. To remove intraluminal cysts in noninvasive colitis, paromomycin can be used. For invasive Amebiasis, metronidazole is the antibiotic of choice. In addition, due to the potential of bacterial translocation in fulminant amoebic colitis, broad-spectrum antibiotics must be added to the therapy.



    Following severe diarrhea, oral rehydration and a bland diet might help the intestines recover. Probiotics aid in the restoration of the normal flora in the intestines and the prevention of illness in the future.


    Differential Diagnosis

    • Irritable bowel syndrome
    • Inflammatory bowel disease
    • Celiac disease
    • Colorectal cancer
    • Diverticulitis
    • Toxic megacolon
    • Viral/bacterial gastroenteritis
    • Other types of colitis
    • Drug-induced colitis
    • Radiation-associated colitis
    • Acute appendicitis/ileocecal mass



    The majority of instances of infectious colitis last seven days, with severe cases lasting several weeks. Prolonged disease, if left untreated, might be mistaken for ulcerative colitis.


    What are the Complications of Colon Infection?

    • Dehydration: Severe diarrhea can result in the loss of electrolytes and water from the body. It can cause dehydration, affecting general health.
    • Kidney failure: Dehydration can cause deterioration of kidney function.  Decreased water absorption from the colon due to infection can overload the kidneys, and the sudden increase in kidney function may lead to kidney failure.
    • Toxic megacolon: is an uncommon condition caused by an infection that causes incapacity to pass gas or stool and bowel becomes bloated. A megacolon is a large, bloated colon. Diseases like ulcerative colitis and pseudomembranous colitis when become complicated, it can cause toxic megacolon in over 60% of patients developing .Other conditions associated with inflammation of colon including Campylobacter and shigella colitis may develop toxic megacolon.
    • Bowel perforation: Infection can cause damage to the lining of the colon walls and produce tears or bowel perforations. Extensive injury can cause the infection to spread into the abdominal cavity from the colon. It results in peritonitis (infection of the abdominal lining).
    • Bowel strictures, fistulas, abscess, and intestinal obstruction
    • Guillain-Barre syndrome (Campylobacter jejuni colitis, CMV)
    • Hemolytic uremic syndrome (enterohemorrhagic E coli, Shigella)
    • Encephalopathy, seizures (Shigella)
    • Reactive arthritis (Shigella, Campylobacter jejuni, Yersinia enterocolitica colitis)


    How Can I Prevent Colon Infection?

    The infections of the colon spread mainly through the fecal-oral route. Many bowel infections can be prevented by taking care with what you eat and drink, and by following good hygiene practices. You can take some measures to prevent the spread of pathogens. Such as:

    • Prepare food in a clean environment.
    • Drink clean water. Water treated with UV and other such agents can kill the infectious pathogens.
    • Cook foods such as meat and eggs thoroughly.
    • Disinfect your surroundings regularly. An unclean environment can harbor several pathogens.
    • Always wash your hands. Washing your hands before preparing, serving, and eating food will remove any surface bacteria.
    • Avoid unnecessary use of antibiotics. Antibiotics can destroy the bacterial fauna of the colon, leaving you exposed to infections.
    • When travelling to developing nations, only use bottled water for drinking and teeth cleaning, and avoid ice and raw foods.
    • Avoid close contact with people who have a bowel infection
    • Patients appearing with proctitis should be screened for sexually transmitted diseases.


     When should I see my doctor?

    Make an appointment to see a doctor if you have:

    • Severe symptoms
    • High temperature
    • Blood or mucus in your stools
    • Diarrhea more  than 2 or 3 days
    • Signs of dehydration, such as excessive thirst or not passing much urine



    If your baby is under 3 months old and has diarrhea, see a doctor right away.


    Children should go to the emergency department if:

    • Presence of signs of dehydration (not passing urine, pale, sunken eyes, cold hands or feet or is very cranky)
    • they can't keep fluids down
    • severe stomach pain
    • Being unwell, including being less responsive, not feeding well


    Toddlers and young children should see a doctor if:

    • Having diarrhea that doesn't go away
    • Blood in the stool
    • Losing weight


    Frequently Asked Questions (FAQs)

    1. How to avoid colon infection when traveling?

    It is easy to get infections while traveling. Ensure to eat at hygienic eateries, drink water from a sealed bottle, and wash hands before eating.


    2. How long does infection last?

    Colon infections usually last up to 7 days. In severe cases, it may also take 3 to 4 weeks to resolve.


    3. What food should I avoid during colon infection?

    Avoid fatty and spicy food if you have colon infections. Also, watch out for dairy products, caffeine, nicotine, alcohol, and processed sugary food.



    Infectious colitis is an inflammation of the colon caused by an infectious agent such as bacteria, viruses, fungi, or parasites. In most cases, the infections are self-limiting; but, if they are neglected, problems might develop. Colon infections may be avoided with appropriate care and sanitation.