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Questions and Answers
What is the principal risk factor for C.difficile infection?
Which antibiotics are most frequently associated with C.difficile infections?
How does C.difficile primarily enter the susceptible host?
Which type of C.difficile toxin is primarily responsible for causing symptoms?
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Which of the following groups is generally at higher risk for C.difficile infections?
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What is the primary approach to diagnosing tetanus?
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Which of the following is NOT part of the treatment for tetanus?
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What is the standard vaccine used to prevent tetanus?
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In what situation should an individual receive a tetanus booster?
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Which type of wound is considered tetanus prone?
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What factor increases the risk associated with certain wounds in relation to tetanus?
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What is the clinical role of human tetanus immunoglobulin (TIG) in the management of tetanus?
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What is a common misconception about recovery from tetanus?
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What is the primary result of botulinum toxin's action at the neuromuscular junction?
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Which form of botulism is most commonly associated with the ingestion of contaminated food?
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What symptom is typically absent in cases of botulism?
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What is a common diagnostic method for confirming foodborne botulism?
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What is a significant preventive measure recommended for infants to avoid botulism?
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Which type of botulism occurs when spores are deposited in open wounds?
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What type of management is specifically used for wound botulism?
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What is the primary cause of perfringens food poisoning?
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What was a notable event related to a botulism outbreak in 2023?
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Which food types are commonly associated with perfringens food poisoning?
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What is the recommended immediate treatment for gas gangrene?
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Which of the following antibiotics is part of the combination therapy for gas gangrene?
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What is an effective way to prevent perfringens food poisoning?
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Which condition is primarily linked to the occurrence of a Clostridium perfringens infection?
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What type of vaccine is used for the prevention of anaerobic infections?
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What is the potential mortality range associated with untreated gas gangrene?
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What is true regarding recurrent Clostridioides difficile infection (CDI)?
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Which symptom is NOT associated with Clostridioides difficile infection (CDI)?
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What is the first step to take if CDI is suspected?
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Which antibiotic is no longer considered the first-line agent for treating CDI?
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Which of the following is a key prevention strategy for CDI?
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What is the primary toxin produced by Clostridium perfringens related to gas gangrene?
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How is Clostridioides difficile primarily diagnosed?
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Which of the following accurately describes the environment in which Clostridium perfringens is commonly found?
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Study Notes
Tetanus
- Tetanus is a clinical diagnosis
- Early recognition is key
- ABCs are essential, some patients may require intubation
- Treat infected source tissue with wound debridement and antimicrobials such as benzylpenicillin or metronidazole
- Neutralize the toxin with human tetanus immunoglobulin (TIG)
- Manage spasms
- Avoid touching, light, and other stimuli
Tetanus Prevention & Immunisation
- Prevented by immunisation with toxoid vaccines
- Recovery from tetanus confers natural immunity
- Majority of cases are birth-associated in newborn babies, mothers not vaccinated
- 86% of infants worldwide vaccinated with 3 doses of diphtheria-tetanus-pertussis (DTP) in 2016
- Toxoid vaccine is part of childhood vaccination programs
- Clinical efficacy is almost 100%, but immunity wanes, and after 10 years may not provide protection
- If the last tetanus shot was more than 10 years ago, individuals may need a booster
Post Exposure Prophylaxis
- Tetanus prone wounds include:
- Puncture type injuries acquired in a contaminated environment
- Wounds containing foreign bodies
- Compound fractures
- Wounds or burns with systemic sepsis
- Some animal bites/scratches (most domestic pets unlikely to have saliva containing spores unless the animal is rooting in soil or lives in an agricultural setting)
- High-risk wounds include:
- Heavy contamination with material likely to contain spores e.g. soil, manure
- Wounds or burns with extensive devitalized tissue (anaerobic environment)
Clostridium Botulinum
- Botulism is a paralytic illness caused by Cl. botulinum neurotoxin
- Botulinum toxin is used medically as “Botox”
- Toxin inhibits the release of acetylcholine at the neuromuscular junction
- Results in weakness/acute flaccid paralysis
- Cl. botulinum can survive in soil and untreated water for protracted periods
- There are several types of botulism:
- Foodborne botulism
- Wound botulism
- Infant botulism
Categories of Botulism
-
Foodborne: Most common form following ingestion of contaminated food (e.g., home canned foods)
- Food contaminated by spores
- If not cooked thoroughly and then put in an anaerobic environment (e.g., sealed jar) spores germinate toxin produced
- If the contaminated food is then eaten = Fast onset of symptoms 12–36 hours after ingestion
- Typically, the food will look and taste normal
-
Wound botulism: Spores deposited in open wounds
- Then germinate and produce toxin
-
Infant botulism: Ingestion of spores (e.g., via food)
- Germinate in the GIT
- Toxin then released in the GIT and absorbed
Botulism Presentation
- Symmetrical descending flaccid paralysis
- Bilateral cranial nerve palsies = double vision, difficulty swallowing
- General muscle weakness
- Respiratory failure without impairment of consciousness
- Fever is classically absent
-
Infant botulism
- Constipation and then muscle weakness / lethargy / poor feeding / ‘floppy’ baby
Botulism Outbreaks
- Outbreak of botulism in Bordeaux, France in 2023 during the rugby world cup
- 15 cases, at least 8 hospitalized and required management in the intensive care unit
- One person died
- Linked to contaminated canned sardines produced at a local restaurant
Botulism Diagnosis & Management
- Clinical picture: History of possible exposure
-
Laboratory tests confirm the diagnosis
- Foodborne: Detect toxin in stool/vomitus
- Infant botulism: Organism or toxin in stool
- Wound: Culture from wound site
-
Management:
- ABC
- Antitoxin: Botulism IG
- There is an infant formulation - BabyBIG
- Wound: Debridement and metronidazole
Botulism Prevention
- Care with home preserving
- Infants: No raw honey less than 12 months
- Hand hygiene and care with food preparation
Clostridioides Difficile
- C. difficile can cause symptoms ranging from diarrhoea to life-threatening inflammation of the colon
- Found in soil, air, water, human & animal faeces
- Spores survive outside of the body
- Up to 1 in 10 healthy adults carry C. difficile in the colon (colonisation)
- 70% of infants but infection is rare
- Infection occurs typically in people in contact with healthcare/been on antibiotics
- Infection with C. difficile occurs in ~half a million people/year in the US
Antibiotics & C. difficile
- Antibiotic use predisposes to colonisation and infection
- Antibiotics are the principal risk factor for infection
- Disruption of normal colonic flora
- Virtually all antibiotics have been implicated
- The most frequently associated are:
- Fluoroquinolones
- β lactam antibiotics, particularly co-amoxiclav, and third generation cephalosporins (cefotaxime and ceftriaxone)
- Clindamycin
- Symptoms and signs are caused by toxins
- There are at least 2 types of toxin: A & B
C. difficile & the Chain of Infection
- Infectious agent: C. difficile
-
Susceptible host: ‘At-risk’ patients or residents
- Advanced age
- Antibiotic use
- Hospitalisation
-
Reservoir: Bowel
- Contaminated environment
- Means of Transmission: Faecal/Oral
-
Contact Transmission:
- Hands
- Equipment
- Environment
Two Categories of C. difficile Infections (CDI)
- New: First episode
-
Recurrent:
- Occurs within 8 weeks after onset of a previous episode
- Risk of recurrence increases with each recurrence
C. difficile Infection Symptoms
- Asymptomatic to potentially fatal
- Diarrhoea
- Fever
- Acute abdomen / pseudomembranous colitis
Responding to Suspected CDI
- Suspect it where there is no clear alternative cause for diarrhoea (e.g., diarrhoea during or after antibiotics)
- Isolate the patient
- Gloves and aprons
- Contact precautions
- Hand washing (not alcohol gel) after each contact with the patient and their environment
- Test the stool for toxin-producing C. difficile
- PCR for the toxin gene
CDI Diagnosis
- Clinical suspicion, e.g. diarrhoea during or after antibiotics
-
Test faeces for C. difficile toxin
- Diarrhoeal specimen – same day test result
- PCR for the presence of toxin gene tcdB - sensitive
- EIA for the presence of toxin – confirmatory, specific
- Diarrhoeal specimen – same day test result
CDI General Treatment Principles
- Isolation + contact precautions
- Review and stop antibiotic(s) if possible: If not, switch to agents with a lower propensity to induce C. difficile infection
- Supportive therapy (fluids etc)
- Antibiotic treatment of CDI:
- (oral) Vancomycin OR
- Fidaxomicin
- Metronidazole no longer first-line agent (reduced efficacy v. vancomycin/fidaxomicin)
Clostridioides Difficile Infection: Prevention & Control
- Antibiotic stewardship
- Infection prevention and control guidelines, e.g., hand hygiene
Clostridioides Perfringens
- Cl. perfringens causes tissue necrosis
- Well known for its association with gas gangrene (clostridial myonecrosis) and emphysematous cholecystitis
- Common cause of food poisoning
- Ingestion of food contaminated with toxin-producing organisms/spores
- Cl. perfringens is ubiquitous in nature
- Decaying vegetation, soil, marine sediment, GIT of humans & animals
Clostridioides Perfringens Clinical Presentation
- Produce many virulent toxins
- Toxin involved in gas gangrene is α toxin, a lecithinase
- Inserts into the cell membrane causing holes and disrupting cellular function
- Cl. perfringens food poisoning is caused by an enterotoxin
- Toxin involved in gas gangrene is α toxin, a lecithinase
-
Food poisoning: After ingestion of contaminated food
- Contaminated meat products (beef, poultry, gravy, dried or precooked foods) served without adequate reheating.
- Abdominal cramps/diarrhoea
- Cellulitis/wound infection: Usually in devitalized tissue
-
Gas gangrene:
- Contaminated wounds with poor blood supply and tissue necrosis
- Progressive invasion and destruction of healthy muscle tissue
Gas Gangrene
- Rapidly progressive infection
- Destruction of muscle
- Severe systemic toxicity
-
Investigations:
- Wound swab/blister fluid for culture
- Blood cultures
-
Management:
- Prompt debridement of all nonviable tissue is essential
-
Antimicrobials:
- Combination therapy:
- High-dose penicillin/clindamycin
- Antitoxin activity
- Combination therapy:
- Mortality: 40-100%
Clostridioides Perfringens Prevention
-
Food Poisoning:
- Cook and keep food at the correct temperature
- Serve meat dishes hot, within 2 hours after cooking
- Refrigerate leftovers and reheat them properly
- When in doubt, throw it out!
-
Cellulitis/Wound Infection, Gas Gangrene:
- Clean wounds thoroughly
- Remove foreign objects and dead tissue from wounds
- IV antibiotic prophylaxis with abdominal surgery
- Skin preparation and administer IV antibiotics if lower limb amputation in patients with peripheral vascular disease
Prevention of Anaerobic Infection
- Non-specific = wound debridement, safe food preparation
- Specific = toxoid vaccine
- Clostridial infections already covered under individual clinical conditions
-
Surgery on bowel:
- Prophylactic antibiotics using an agent with anaerobic cover
- Care with surgery to avoid/minimise the risk of spillage of bowel content into the peritoneal cavity
- If peritoneal contamination occurs, treat with appropriate antimicrobial
Summary: Anaerobic Bacteria
- Anaerobic bacteria are ubiquitous in nature and as part of normal flora
- Predisposing conditions include trauma, necrosis, and ischemia
- Spore-forming include clostridia that produce toxins with characteristic presentations (e.g., C. tetani)
- Clostridioides difficile is a major cause of healthcare-associated diarrhea
- Anaerobic Gram-negative bacilli such as Prevotella spp.
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Description
This quiz covers the clinical aspects of tetanus, including diagnosis, treatment, and prevention strategies. Learn about the importance of immunization and the management of tetanus-prone wounds. Test your knowledge on the efficacy of vaccines and post-exposure prophylaxis for tetanus.
