What antibiotics are used to treat infectious colitis?

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Last updated: April 23, 2025View editorial policy

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From the Guidelines

Antibiotics should be used judiciously in the treatment of infectious colitis, with oral vancomycin 125mg four times daily for 10 days being the first-line therapy for Clostridioides difficile colitis, as recommended by the most recent and highest quality study 1.

Key Considerations

  • The decision to use antibiotics should be based on the severity of illness, patient risk factors, and stool culture results when available.
  • For empiric treatment of suspected bacterial colitis, ciprofloxacin 500mg twice daily or azithromycin 500mg on day 1 followed by 250mg daily for 4 days can be used.
  • Most viral and many bacterial causes of colitis are self-limiting and require only supportive care with hydration and electrolyte replacement.
  • Antibiotics should be avoided in suspected E. coli O157:H7 infections as they may increase the risk of hemolytic uremic syndrome.

Treatment Options

  • For Clostridioides difficile colitis, fidaxomicin 200mg twice daily for 10 days is an alternative to vancomycin.
  • For Shigella, ciprofloxacin 500mg twice daily for 3 days is effective.
  • For Campylobacter infections, azithromycin 500mg daily for 3 days is effective.

Important Notes

  • Overuse of antibiotics can lead to resistance and disruption of gut microbiota, potentially worsening or prolonging symptoms.
  • Fecal microbiota transplantation (FMT) is an effective option for patients with multiple CDI recurrences who have failed appropriate antibiotic treatments 1.
  • Coadjuvant treatment with monoclonal antibodies (bezlotoxumab) may prevent recurrences of CDI, particularly in patients with CDI due to the 027 epidemic strain, in immunocompromised patients and in patients with severe CDI 1.

From the FDA Drug Label

Vancomycin Hydrochloride Capsules are indicated for the treatment of C. difficile-associated diarrhea. Vancomycin Hydrochloride Capsules are also used for the treatment of enterocolitis caused by Staphylococcus aureus (including methicillin-resistant strains) in adult and pediatric patients less than 18 years of age

Antibiotics for infectious colitis:

  • Vancomycin Hydrochloride Capsules are indicated for the treatment of C. difficile-associated diarrhea and enterocolitis caused by Staphylococcus aureus.
  • The recommended dose for C. difficile-associated diarrhea is 125 mg administered orally 4 times daily for 10 days.
  • The recommended dose for staphylococcal enterocolitis is 500 mg to 2 g administered orally in 3 or 4 divided doses for 7 to 10 days 2.

From the Research

Antibiotics for Infectious Colitis

  • The use of antibiotics for infectious colitis depends on the cause of the infection, with most forms being treatable with antimicrobials 3.
  • For empiric treatment of febrile dysenteric diarrhea, invasive bacterial enteropathogens such as Shigella, Salmonella, and Campylobacter should be suspected, and adults may be treated empirically with 1000mg azithromycin in a single dose 4.
  • Pathogen-specific antimicrobial therapy should be initiated for all forms of infectious colitis other than Shiga toxin-producing Escherichia coli (STEC) 4.

Treatment of Clostridioides difficile Infection

  • Vancomycin and metronidazole are commonly used for the treatment of Clostridioides difficile infection (CDI), with vancomycin being more effective in severe cases 5.
  • Fidaxomicin has been shown to be superior to metronidazole, vancomycin, and their combination for the treatment of CDI, particularly in the initial episode, first recurrence, and non-severe cases 6.
  • The susceptibility of C. difficile to metronidazole and vancomycin can vary, with rates of resistance to metronidazole and intermediate resistance to vancomycin being higher among isolates from human immunodeficiency virus-infected patients 7.

Diagnostic Approaches

  • Standard stool culture should be performed in patients with infectious colitis, and epidemiologic findings may suggest the need for specialized studies of etiology 4.
  • Multiplex polymerase chain reaction (PCR) followed by guided culture on PCR-positive pathogens can often confirm active infection, while standard culture methods provide isolates for antibiotic susceptibility testing, subtyping, and Whole Genome Sequencing 3.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Approach to the patient with infectious colitis.

Current opinion in gastroenterology, 2012

Research

Oral vancomycin versus metronidazole for the treatment of Clostridioides difficile infection: Meta-analysis of randomized controlled trials.

Journal of infection and chemotherapy : official journal of the Japan Society of Chemotherapy, 2018

Research

Fidaxomicin versus metronidazole, vancomycin and their combination for initial episode, first recurrence and severe Clostridioides difficile infection - An observational cohort study.

International journal of infectious diseases : IJID : official publication of the International Society for Infectious Diseases, 2021

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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