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This article is for Medical Professionals

Professional Reference articles are designed for health professionals to use. They are written by UK doctors and based on research evidence, UK and European Guidelines. You may find the Clostridium Difficile (C. Diff) article more useful, or one of our other health articles.

Read COVID-19 guidance from NICE

Treatment of almost all medical conditions has been affected by the COVID-19 pandemic. NICE has issued rapid update guidelines in relation to many of these. This guidance is changing frequently. Please visit to see if there is temporary guidance issued by NICE in relation to the management of this condition, which may vary from the information given below.

Clostridia are anaerobic, Gram-positive, spore-forming rods widely distributed in nature, particularly in soil. They form resistant spores under stress. These spores, which can survive brief heating to 100°C, and the powerful exotoxins the active bacteria produce, are central to the medical importance of the species.

Can be caused by various clostridia - eg, Clostridium perfringens, Clostridium septicum, Clostridium novyi and Clostridium histolyticum. See the separate Gas Gangrene article.

Caused by Clostridium tetani. See the separate Tetanus and Tetanus Vaccination article.

Caused by Clostridium difficile. See the separate Pseudomembranous Colitis article.

Editor's note

Dr Sarah Jarvis, 27th July 2021

New NICE guidance on antimicrobial prescribing in Clostridioides difficile infection
The National Institute for Health and Care Excellence (NICE) has issued new guidance on Clostridioides difficile infection.[1] This includes full guidance on assessment, concomitant medication and management, including antimicrobial prescribing. Full details are included in the article on Pseudomembranous Colitis.

Caused by a neurotoxin of Clostridium botulinum. See the separate Botulism article.

Botulism and bioterrorism

  • The most toxic substance known to man.[2] A lethal dose is <1 microgram.
  • A deliberate release may involve airborne dissemination of toxin, or contamination of food or water supplies with toxin or bacteria.
  • Water treatment inactivates the toxin, the toxin cannot penetrate intact skin and it loses activity within a few days.
  • The most likely scenarios would therefore be:
    • A deliberate contamination of foodstuffs; large doses may lead directly to neurological symptoms without the gastrointestinal symptoms of nausea, vomiting and diarrhoea followed by constipation.
    • Aerosol release; most effective in an enclosed environment. After inhalation, the onset of symptoms may be as rapid as <1 hour. However, in cases of accidental inhalation symptom onset can be 3-4 days.

This is the fourth most common form of food-borne illness, after Norwalk-like viruses, Campylobacter spp. and Salmonella spp.

  • Spores survive cooking, and germinate during slow cooling or unrefrigerated storage.[3] They produce exotoxin, requiring a large infective dose.[4]
  • It is mostly associated with meat and poultry, usually occurring in schools, hospitals, factories and catering establishments.Typically, a meat dish is stewed or boiled and allowed to stand for 4-24 hours and then served without adequate reheating.
  • 6-12 hours later the patient suffers crampy abdominal pain followed by diarrhoea, which subsides 12-24 hours later.
  • Clinically it appears similar to gas gangrene, now rare in UK with the legalisation of abortions.
  • Formerly the leading cause of maternal death worldwide, it is still a problem in developing countries, due to illegal abortions and poor obstetric practice.
  • Two major factors are involved:[5]
    • Infection, which is commonly caused by C. perfringens in mixed infection with non-sporing anaerobes (eg, Bacteroides spp.), Group B beta-haemolytic streptococci, staphylococci, or Escherichia coli, Neisseria gonorrhoeae, Chlamydia trachomatis and Mycoplasma spp.
    • Retained products of conception.

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Further reading and references

  1. Clostridioides difficile infection: antimicrobial prescribing; NICE Guidance (July 2021)

  2. Osborne SL, Latham CF, Wen PJ, et al; The Janus faces of botulinum neurotoxin: Sensational medicine and deadly biological weapon. J Neurosci Res. 2007 May 185(6):1149-58.

  3. de Jong AE, Rombouts FM, Beumer RR; Behavior of Clostridium perfringens at low temperatures. Int J Food Microbiol. 2004 Dec 197(1):71-80.

  4. Uzal FA, Freedman JC, Shrestha A, et al; Towards an understanding of the role of Clostridium perfringens toxins in human and animal disease. Future Microbiol. 20149(3):361-77. doi: 10.2217/fmb.13.168.

  5. Eschenbach DA; Treating spontaneous and induced septic abortions. Obstet Gynecol. 2015 May125(5):1042-8. doi: 10.1097/AOG.0000000000000795.