Clostridium perfringens: Infectious substances pathogen safety data sheet 

To learn about Clostridium perfringens infection, its causes, symptoms, risks, treatment and prevention, see the following:

• Clostridium perfringens infection

Section I – Infectious agent

Name

Clostridium perfringens

Agent type

Bacteria

Taxonomy

Family

Clostridiaceae

Genus

Clostridium

Species

Perfringens

Synonym or cross-reference

Bacillus aerogenes capsulatus, Bacillus perfringens, Bacillus welchii and Clostridium welchii^{Footnote 1}.

Characteristics

Brief description

Clostridium perfringens (C. perfringens) is non-motile, anaerobic, gram-positive spore forming bacteria^{Footnote 2}. Vegetative cells are rod shaped, pleomorphic, and occur in pairs or short chains^{Footnote 3}. C. perfringens has 7 toxigenic types (A-G), of which A, C and F strains are pathogenic for humans^{Footnote 4 Footnote 5}. Colonies with double zone of hemolysis are produced when cultured at 37^oC on blood agar overnight^{Footnote 2}. The genome of C. perfringens ranges in size from 3.0-4.1 Mb and contains 2500-3600 genes^{Footnote 6}. Many of the ∼16 toxins produced by C. perfringens are encoded by large plasmids that range in size from ∼45 kb to ∼140 kb^{Footnote 7}. These plasmid-encoded toxins are often closely associated with mobile elements.

Properties

C. perfringens has a number of characteristics that allow it to infect hosts more efficiently including oxygen tolerance, the ability to form highly resistant spores, the selectivity of germinants (agents that induce germination from spores), the ability to form biofilms and its ability to proliferate rapidly^{Footnote 8 Footnote 9 Footnote 10 Footnote 11}. Its aero-tolerance allows it to persist in oxygen rich environments increasing risk of exposure and also allows for infection of oxygen-exposed wounds^{Footnote 12}. Sporulation allows C. perfringens to survive in aerobic environments, extremes of temperature and nutrient-depleted environments aiding in its dissemination as well as being a major factor in its ability to cause food poisoning^{Footnote 13}. Germinants of C. perfringens include primary bile acids in the human gastrointestinal track as these signal spore germination, growth and colonization of the intestines^{Footnote 9 Footnote 14}. C. perfringens has a very rapid growth rate (8-12 minute doubling time) which allows for rapid proliferation and the out competing of other bacteria that are found in the gastrointestinal tract^{Footnote 11}.

C. perfringens produces 6 major toxins that are involved in both human and animal disease alpha, beta, epsilon, iota, enterotoxin and necrotic B-like^{Footnote 5}. Alpha toxin is essential for gas gangrene (clostridial myonecrosis) development and is produced by all strains of C. perfringens^{Footnote 15}. It has the ability to hydrolyse cell membrane phospholipids leading to cell necrosis^{Footnote 16}. Beta toxin (CPB) is found in types B and C strains and is a pore-forming intestinal necrotic that causes hemorrhage and necrosis of the epithelium of the small and large intestine in humans and animals^{Footnote 15 Footnote 17}. Epsilon toxin is among the most toxic toxins known (LD₅₀ 70 ng/kg), and is produced by C. perfringens types B and D causing enterotoxaemia in goats and sheep^{Footnote 18 Footnote 19}. It increases intestinal permeability which allows it to enter the bloodstream where it affects endothelial cells and targets the brain, lung, heart and kidney^{Footnote 15}. Iota toxin damages the actin cytoskeleton of cells leading to apoptosis and is produced by type E strains of C. perfringens^{Footnote 5 Footnote 20}. C. perfringens enterotoxin is produced by strains C-F and forms pores in epithelial and endothelial cells through claudin tight junction binding^{Footnote 15 Footnote 21}. Type G strains of C. perfringens produce necrotic B-like toxin^{Footnote 15}. It is a pore-forming toxin causing avian necrotic enteritis in chickens^{Footnote 22 Footnote 23}.

Section II – Hazard identification

Pathogenicity and toxicity

C. perfringens is capable of causing a range of diseases in a number of economically important animal species as well as humans^{Footnote 1 Footnote 24}. In humans, infection with ­C. perfringens takes several forms depending on the method of infection and the strain type involved.

C. perfringens (type A) is the most common cause of clostridial myonecrosis (gas gangrene) in humans and mammals^{Footnote 15}. The disease involves breakdown of muscle and sub-cutaneous tissue due to the actions of alpha toxin: hemolysis, myonecrosis, leukostasis, platelet aggregation, vasoconstriction and inhibition of neutrophil differentiation. It is manifested by severe pain, edema, tenderness and pallor, followed by discoloration and hemorrhagic bullae, and production of gas at the site of wound. Systemic manifestations of the disease include shock, renal failure, hypotension, bacteremia with intravascular hemolysis leading to coma and death. With prompt diagnosis and treatment the mortality rate is 5-30%, however without treatment, the fatality rate is almost 100%.

Food poisoning can be caused by C. perfringens (types A and F) enterotoxin (CPE) produced by C. perfringens spores in the small intestine, which can germinate in foods such as meat and poultry^{Footnote 15}. The consumption of large amounts of C. perfringens is considered an important cause of watery diarrhea^{Footnote 1}. Main symptoms of the disease are intestinal cramps, nausea, and diarrhea. The disease is usually mild and self-limiting in healthy individuals, with symptoms resolving within 24 hours and mortality being rare^{Footnote 1 Footnote 15}. Non-foodborne diarrhea is similar to the food borne but normally has more severe symptoms and a longer duration (3 days to several weeks).

C. perfringens infection is the most common cause of clostridial cellulitis, which is often associated with local trauma or recent surgery^{Footnote 25}. Infection is less systemic than in clostridial myonecrosis, with localized infection and associated skin and soft tissue necrosis, but sparing of the fascia and deep muscles.

Enteritis necroticans (Pigbel/Darmand) is a life threatening infection caused by C. perfringens type C, and is marked by hemorrhagic, inflammatory, or ischemic necrosis of the jejunum^{Footnote 15}. Clinically the disease causes diarrhea and abdominal pain with neurologic disruptions and death occurring occasionally^{Footnote 1}.

Infection of pre-term infants with C. perfringens, either types A or C, can cause necrotizing enterocolitis (NEC)^{Footnote 1}. Pre-term infants weighing less than 1 kg have a 14% prevalence of NEC and up to a 50% mortality rate. Symptoms include abdominal pain and swelling, bloody diarrhea and lethargy.

In sheep, C. perfringens type A causes yellow lamb disease in recently weaned lambs^{Footnote 26}. Infected lambs usually succumb to the disease before a diagnosis can be made and anaemia, jaundice and hamoglobinuria are routinely observed post-mortem. Lamb dysentery is caused by C. perfringens type B and affects lambs up to three weeks old but is more common in new born lambs as colostrum provides protection in older lambs. Mortality rate can be as high as 20% with multi focal haemorrhages of the small and large intestine prevalent. C. perfringens type D causes enterotoxaemia in young sheep and adults as well as goats^{Footnote 24}. Symptoms include sudden death, blindness, convulsions, bleating, frothing of the mouth and recumbency with paddling before death.

In suckling piglets C. perfringens type A causes a non-haemorrhagic enterocolitis^{Footnote 1}. Symptoms include severe diarrhea accompanied by reduction in feeding and weight loss^{Footnote 24}. Although disease is in general mild, morbidity is possible. A more serious haemorrhagic enteritis in piglets is caused by C. perfringens type C. In this infection pigs rapidly become ill with dysenteric diarrhea and often are not found until they have succumb to the disease.

Infections of chickens with C. perfringens type G can be clinical or sub-clinical in nature and is more prevalent in developing chicks^{Footnote 27}. When clinical symptoms of this necrotic enteritis are present they include sudden death (up to 50% of a flock), depression, dehydration, drowsiness, diarrhea and decreased appetite.

Primarily in young foals but occasionally in adult horses, C. perfringens type C can cause necrotic enteritis^{Footnote 28}. Clinical symptoms include colic, lethargy, depression, pyrexia and bloody diarrhea. In severe cases neurologic symptoms and death can occur.

Cattle are rarely infected but cases of young calves, a six month old heifers and two adult cows infected with C. perfringens type D have been reported^{Footnote 24}. In the young calves rapid death occurred, while in the older cows laboured breathing, as well as neurological symptoms such as ear twitching, neck extension, eyelid flickering and blindness occurred.

Epidemiology

C. perfringens is a common member of the gastrointestinal flora of humans and animals^{Footnote 1}. Food poisoning caused by C. perfringens is one of the most common causes of food poisoning in the world. Contaminated food, usually cooked meat, vegetables, fish or poultry dishes that have been undercooked or stored at ambient temperatures for a long time after cooking are responsible for outbreaks in developed countries. There are an estimated 1 million cases of food borne illness every year in the United States and 5 million cases in the European Union member countries^{Footnote 1 Footnote 15}. Deaths due to the disease are rare and occur mainly in elderly, debilitated, or individuals predisposed to the disease.

C. perfringens is the most common cause of trauma-associated gas gangrene accounting for 80-90% of cases^{Footnote 29}. In the United States, 1000-3000 cases are reported yearly and it is thought to be more prevalent in developing countries. The World Health Organization reported that many injured people in the Schezuan earthquake in China in 2008 developed gas gangrene^{Footnote 30}. Furthermore, from April-August 2000, 55 drug users in Scotland developed severe soft tissue infections, 8 of which were due to C. perfringens, after injecting contaminated heroin^{Footnote 31}.

Enteritis necroticans was first recognized as a frequent cause of death among children in New Guinea in the 1960s^{Footnote 32}. It has also been reported to occur among malnourished adults or people with chronic diseases such as diabetes in USA, United Kingdom, Germany and other developed nations^{Footnote 33 Footnote 34}.

Injection drug users are more susceptible to skin and soft tissue infections^{Footnote 35}. Patients with gastric and intestinal cancer can have higher rates of C. perfringens bacteremia^{Footnote 36}. Non-foodborne diarrhea is found in 5-25% of patients administered broad-spectrum antibiotics^{Footnote 1}.

Host range

Natural host(s)

C. perfringens is a member of the gastrointestinal flora of and can infect humans and a large number of mammals (cattle, sheep, goats, chickens, pigs, cats and dogs) as well as poultry^{Footnote 1 Footnote 15 Footnote 37}.

Other host(s)

Experimentally infected animals include mice, rats, rabbits and cynomolgus monkeys^{Footnote 38}.

Infectious dose

For clostridial food poisoning ingestion of food containing 10^{Footnote 8} or more viable vegetative C. perfringens cells can result in food poisoning^{Footnote 34}.

Incubation period

For clostridial food poisoning: 8-24 hours while for gas gangrene 1-4 days after the injury^{Footnote 1}.

Communicability

In humans, food-borne illness is acquired by ingestion of large number of C. perfringens vegetative cells present in the food^{Footnote 15}. Food sources are usually cooked meat, vegetables, fish or poultry dishes that have been undercooked or stored at ambient temperatures for a long time after cooking. Not directly transmitted from person to person.

Enteritis necroticans has been linked to the ingestion of contaminated and undercooked pork meat^{Footnote 1}.

Gas gangrene and clostridial cellulitis infection can occur through contamination of wounds (fractures, bullet wounds) with dirt or any foreign material contaminated with C. perfringens^{Footnote 15}.

Animals can be infected through soil but C. perfringens is also a member of the gastrointestinal flora of many animals both diseased and non-diseased with infection and symptoms of disease present when gut conditions promote both C. perfringens growth and toxin stability^{Footnote 1 Footnote 24}.

Section III – Dissemination

Reservoir

C. perfringens is a member of the gastrointestinal flora of healthy humans and a large number of mammals (cattle, sheep, goats, chickens, pigs, cats and dogs) as well as poultry^{Footnote 1}.

Zoonosis

None.

Vectors

None.

Section IV – Stability and viability

Drug susceptibility/resistance

Susceptible to many antibiotics such as penicillin, clarithromycin, clindamycin, metronidazole, vancomycin, lincomycin and tetracyclines^{Footnote 4 Footnote 39}.

Resistance to the single antibiotics chloramphenicol, bactracin, tetracycline, lincomycin, erythromycin as well as multidrug strains resistant to tetracycline, erythromycin, clindamycin and lincomycin have been observed^{Footnote 1 Footnote 40}.

Susceptibility to disinfectants

Spores of Clostridium species can be killed by high level disinfectants such as 2% aqueous glutaraldehyde within 3 hours, and 8% formaldehyde^{Footnote 41 Footnote 42}. C. perfringens spores are resistant to most disinfectants and when susceptible, they require longer contact time. Clostridium spores are resistant to ethyl and propyl alcohols as well as chlorine dioxide^{Footnote 41 Footnote 43}.

Physical inactivation

Spores are highly resistant to both high and low temperature extremes, osmotic pressure and pH^{Footnote 15}. Vegetative cells can be rapidly killed by dry heat at 160-170°C for 1-2 hours or moist heat at 121°C for 15-30 minutes^{Footnote 44}.

Survival outside host

Spores can survive in soil, food, decaying vegetation, marine sediments, and in the anaerobic conditions inside the meat, animal carcasses, feces, dehydrated and cooked food^{Footnote 1 Footnote 15}. Vegetative cells can survive in oxygen rich environments for up to 72 hours^{Footnote 12}.

Section V – First aid/medical

Surveillance

Diagnosis consists of first isolating C. perfringens by culturing on tryptose sulfite cycloserine egg yolk agar; anaerobically for 18-24 (black colonies would be indicative for C. perfringens)^{Footnote 1}. PCR amplification of the 16s RNA or mass spectrum (MALDI-TOF) can then be used to confirm identification. Once identification is confirmed to be C. perfringens typing can be performed by amplifying toxin genes using multiplex PCR.

Microscopic primary diagnosis for gas gangrene and anaerobic cellulitis can consist of direct Gram stain smear of the wound for the presence of short chains of large, fat gram positive rods with blunt ends from symptomatic patients^{Footnote 34}.

Note: The specific recommendations for surveillance in the laboratory should come from the medical surveillance program, which is based on a local risk assessment of the pathogens and activities being undertaken, as well as an overarching risk assessment of the biosafety program as a whole. More information on medical surveillance is available in the Canadian Biosafety Handbook.

First aid/treatment

Food poisoning caused by C. perfringens is usually self-limiting and treatment is supportive^{Footnote 4}.

Treatment of gas gangrene and anaerobic cellulitis involves excision of all devitalized tissue in conjunction with antibiotic therapy with penicillin G and using hyperbaric oxygenation in adjunctive therapy^{Footnote 15 Footnote 38}.

Clostridial necrotizing enteritis including enteritis necroticans and clostridial sepsis are treated with early antibiotic treatment with penicillin G and clindamycin, tetracycline, or metronidazole in combination with surgical debridement of necrotic tissue^{Footnote 45 Footnote 46}.

Note: The specific recommendations for first aid/treatment in the laboratory should come from the post-exposure response plan, which is developed as part of the medical surveillance program. More information on the post-exposure response plan can be found in the Canadian Biosafety Handbook.

Immunization

Vaccination against CPB toxin of C. perfringens type C which causes enteritis necroticans was reported to decrease the incidence of the disease in New Guinea^{Footnote 34 Footnote 47}. Crude and bacterial toxoid vaccines for type B, C and D have been effective in piglets, cattle, lambs, sheep and goats^{Footnote 47}. In Canada, a vaccine for prevention of necrotic enteritis in broiler chickens has been available since 2021^{Footnote 48 Footnote 49}.

Note: More information on the medical surveillance program can be found in the Canadian Biosafety Handbook, and by consulting the Canadian Immunization Guide.

Prophylaxis

None.

Note: More information on prophylaxis as part of the medical surveillance program can be found in the Canadian Biosafety Handbook.

Section VI – Laboratory hazard

Laboratory-acquired infections

None have been reported to date.

Note: Please consult the Canadian Biosafety Standard and Canadian Biosafety Handbook for additional details on requirements for reporting exposure incidents.

Sources/specimens

Human feces, suspect food in a food borne illness, blood, bowel luminal contents or tissue from the involved bowel in case of enteritis necroticans, wound exudates^{Footnote 34}.

Primary hazards

Accidental ingestion of toxins, direct contact of open wounds/site of injury with the pathogen, accidental parenteral inoculation of toxins^{Footnote 34}.

Special hazards

None.

Section VII – Exposure controls/personal protection

Risk group classification

Clostridium perfringens is a Risk Group 2 Human Pathogen and Risk Group 2 Animal Pathogen^{Footnote 50}.

Containment requirements

Containment Level 2 facilities, equipment, and operational practices outlined in the Canadian Biosafety Standard for work involving infectious or potentially infectious materials, animals, or cultures.

Protective clothing

The applicable Containment Level 2 requirements for personal protective equipment and clothing outlined in the Canadian Biosafety Standard are to be followed. The personal protective equipment could include the use of a labcoat and dedicated footwear (e.g., boots, shoes) or additional protective footwear (e.g., boot or shoe covers) where floors may be contaminated (e.g., animal cubicles, PM rooms), gloves when direct skin contact with infected materials or animals is unavoidable, and eye protection where there is a known or potential risk of exposure to splashes.

Note: A local risk assessment will identify the appropriate hand, foot, head, body, eye/face, and respiratory protection, and the personal protective equipment requirements for the containment zone and work activities must be documented.

Other precautions

A biological safety cabinet (BSC) or other primary containment devices to be used for activities with open vessels, based on the risks associated with the inherent characteristics of the regulated material, the potential to produce infectious aerosols or aerosolized toxins, the handling of high concentrations of regulated materials, or the handling of large volumes of regulated materials.

Use of needles and syringes are to be strictly limited. Bending, shearing, re-capping, or removing needles from syringes to be avoided, and if necessary, performed only as specified in standard operating procedures (SOPs). Additional precautions are required with work involving animals or large-scale activities.

For diagnostic laboratories handling primary specimens that may contain C. perfringens, the following resources may be consulted:

• Human Diagnostic Activities Biosafety Guideline
• Local Risk Assessment Biosafety Guideline

Section VIII – Handling and storage

Spills

Allow aerosols to settle. Wearing personal protective equipment, gently cover the spill with absorbent paper towel and apply suitable disinfectant, starting at the perimeter and working towards the centre. Allow sufficient contact time with the disinfectant before clean up (Canadian Biosafety Handbook).

Disposal

All materials/substances that have come in contact with the regulated materials to be completely decontaminated before they are removed from the containment zone or standard operating procedures (SOPs) to be in place to safely and securely move or transport waste out of the containment zone to a designated decontamination area / third party. This can be achieved by using decontamination technologies and processes that have been demonstrated to be effective against the regulated material, such as chemical disinfectants, autoclaving, irradiation, incineration, an effluent treatment system, or gaseous decontamination (Canadian Biosafety Handbook).

Storage

The applicable Containment Level 2 requirements for storage outlined in the Canadian Biosafety Standard are to be followed. Primary containers of regulated materials removed from the containment zone to be labelled, leakproof, impact resistant, and kept either in locked storage equipment or within an area with limited access.

Section IX – Regulatory and other information

Canadian regulatory information

Controlled activities with C. perfringens require a Pathogen and Toxin licence issued by the Public Health Agency of Canada^{Footnote 51}. C. perfringens is a terrestrial animal pathogen in Canada; therefore, its importation requires an import permit under the authority of the Health of Animals Regulations (HAR). The PHAC issues a "Pathogen and Toxin Licence document" for both a Humans Pathogens and Toxins Licence and HAR importation permit.

The following is a non-exhaustive list of applicable designations, regulations, or legislations

• Human Pathogens and Toxins Act and Human Pathogens and Toxins Regulations
• Health of Animals Act and Health of Animals Regulations

Last file update

September, 2022

Prepared by

Centre for Biosecurity, Public Health Agency of Canada.

Disclaimer

The scientific information, opinions, and recommendations contained in this Pathogen Safety Data Sheet have been developed based on or compiled from trusted sources available at the time of publication. Newly discovered hazards are frequent and this information may not be completely up to date. The Government of Canada accepts no responsibility for the accuracy, sufficiency, or reliability or for any loss or injury resulting from the use of the information.

Persons in Canada are responsible for complying with the relevant laws, including regulations, guidelines and standards applicable to the import, transport, and use of pathogens in Canada set by relevant regulatory authorities, including the Public Health Agency of Canada, Health Canada, Canadian Food Inspection Agency, Environment and Climate Change Canada, and Transport Canada. The risk classification and related regulatory requirements referenced in this Pathogen Safety Data Sheet, such as those found in the Canadian Biosafety Standard, may be incomplete and are specific to the Canadian context. Other jurisdictions will have their own requirements.

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