clostridium perfringens the agent of - gangrene - food poisoning bacteria features: gpb, capsulate,...

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Clostridium Clostridium perfringens perfringens The agent of The agent of - Gangrene - Food poisoning Bacteria features: GPB, Capsulate, non-motile. Spores: bulging Rapidly growing (doubling time ~ 8min) specially on soil.

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Page 1: Clostridium perfringens The agent of - Gangrene - Food poisoning Bacteria features: GPB, Capsulate, non-motile. Spores: bulging Rapidly growing (doubling

Clostridium perfringensClostridium perfringens

The agent of The agent of - Gangrene - Food poisoning

Bacteria features:GPB, Capsulate, non-motile. Spores: bulgingRapidly growing (doubling time ~ 8min) specially

on soil.

Page 2: Clostridium perfringens The agent of - Gangrene - Food poisoning Bacteria features: GPB, Capsulate, non-motile. Spores: bulging Rapidly growing (doubling
Page 3: Clostridium perfringens The agent of - Gangrene - Food poisoning Bacteria features: GPB, Capsulate, non-motile. Spores: bulging Rapidly growing (doubling
Page 4: Clostridium perfringens The agent of - Gangrene - Food poisoning Bacteria features: GPB, Capsulate, non-motile. Spores: bulging Rapidly growing (doubling
Page 5: Clostridium perfringens The agent of - Gangrene - Food poisoning Bacteria features: GPB, Capsulate, non-motile. Spores: bulging Rapidly growing (doubling
Page 6: Clostridium perfringens The agent of - Gangrene - Food poisoning Bacteria features: GPB, Capsulate, non-motile. Spores: bulging Rapidly growing (doubling

Colonies:Colonies:On blood agar: β-haemolytic, flat, spreading, rough,

translucent colonies with irregular margins.

Page 7: Clostridium perfringens The agent of - Gangrene - Food poisoning Bacteria features: GPB, Capsulate, non-motile. Spores: bulging Rapidly growing (doubling

Determinants of pathogenicity

• 12 exotoxins and an enterotoxin• The major exotoxins: alpha toxin, beta toxin, epsilon-toxin and Theta-toxin.

• Types of the organism (A through E) can be differentiated according to the toxin repertoire.

• Alpha toxin (Lecithinase) is the primary toxin and common to all types of C. perfringens but mostly by type A.

Page 8: Clostridium perfringens The agent of - Gangrene - Food poisoning Bacteria features: GPB, Capsulate, non-motile. Spores: bulging Rapidly growing (doubling

Determinants of pathogenicity

Lecithinase (or phospholipase) degrades Lecithin in cell membrane into PhosphorylcholinePhosphorylcholine and DiglycerideDiglyceride.

• Hyaluronidase produced by C. perfringens breaks down the intraceullar cytoskeleton.

• Collagenase and other proteinases break down muscles and liquiefy.

• Dnase• Enterotoxin

Page 9: Clostridium perfringens The agent of - Gangrene - Food poisoning Bacteria features: GPB, Capsulate, non-motile. Spores: bulging Rapidly growing (doubling

Nagler reactionNagler reaction• It is done in: A Nagler agar plate,

containing 5-10% egg yolk.• It is used to identify strains produceing

α-toxin (phospholipase).• C. perfringens phospholipase causes

turbidity (characteristic precipitate) around the colonies on egg-yolk medium Inhibited by specific antiserum.

Page 10: Clostridium perfringens The agent of - Gangrene - Food poisoning Bacteria features: GPB, Capsulate, non-motile. Spores: bulging Rapidly growing (doubling
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One-half of the plate is inoculated with antitoxin to act as a control in the identification.

Page 12: Clostridium perfringens The agent of - Gangrene - Food poisoning Bacteria features: GPB, Capsulate, non-motile. Spores: bulging Rapidly growing (doubling

Heat resistancyHeat resistancy

• Type A strains (causing gas gangrene): produce heat inactivated spores

quickly.

• Food poisoning strains: produce heat resistant spores.

Page 13: Clostridium perfringens The agent of - Gangrene - Food poisoning Bacteria features: GPB, Capsulate, non-motile. Spores: bulging Rapidly growing (doubling

TransmissionTransmission• A saprophyte, occuring in soil,

H2O, decomposing plant, human and animal feces.• Vegetative cells are members of

normal flora in colon and 5% of female genital systems (vagina).

Page 14: Clostridium perfringens The agent of - Gangrene - Food poisoning Bacteria features: GPB, Capsulate, non-motile. Spores: bulging Rapidly growing (doubling

GangreneGangrene• Gangrene is necrosis and putrefaction of

tissues. Gas production forms bubbles of gas in muscle (crepitus) and smell in decomposing tissue.

• Gangrene is mostly a mix infection mainly by C. perfringens but also C. septicum, D. sordelli & other proteolitic clusteridums, cocci, gram negative bacilli…. may be found.

Page 15: Clostridium perfringens The agent of - Gangrene - Food poisoning Bacteria features: GPB, Capsulate, non-motile. Spores: bulging Rapidly growing (doubling

Clinical findingsClinical findings

• Glycogen metabolism: Myonecrosis

Bad smelling exuda, inflamation, very progressive necrosis, fever, hemolysis, Crepitation, hemolytic anemia, severe toxemia, shock.

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Crepitation

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• Gangrene is associated with war war and truma wounds.and truma wounds.• Also after:Also after:- Illegal abortion Illegal abortion (causing GangreneGangrene or

Toxic shock syndrome)Toxic shock syndrome)

- 1-3 days after infant delivery infant delivery (Endometric infection).

Page 18: Clostridium perfringens The agent of - Gangrene - Food poisoning Bacteria features: GPB, Capsulate, non-motile. Spores: bulging Rapidly growing (doubling
Page 19: Clostridium perfringens The agent of - Gangrene - Food poisoning Bacteria features: GPB, Capsulate, non-motile. Spores: bulging Rapidly growing (doubling
Page 20: Clostridium perfringens The agent of - Gangrene - Food poisoning Bacteria features: GPB, Capsulate, non-motile. Spores: bulging Rapidly growing (doubling
Page 21: Clostridium perfringens The agent of - Gangrene - Food poisoning Bacteria features: GPB, Capsulate, non-motile. Spores: bulging Rapidly growing (doubling
Page 22: Clostridium perfringens The agent of - Gangrene - Food poisoning Bacteria features: GPB, Capsulate, non-motile. Spores: bulging Rapidly growing (doubling
Page 23: Clostridium perfringens The agent of - Gangrene - Food poisoning Bacteria features: GPB, Capsulate, non-motile. Spores: bulging Rapidly growing (doubling
Page 24: Clostridium perfringens The agent of - Gangrene - Food poisoning Bacteria features: GPB, Capsulate, non-motile. Spores: bulging Rapidly growing (doubling
Page 25: Clostridium perfringens The agent of - Gangrene - Food poisoning Bacteria features: GPB, Capsulate, non-motile. Spores: bulging Rapidly growing (doubling
Page 26: Clostridium perfringens The agent of - Gangrene - Food poisoning Bacteria features: GPB, Capsulate, non-motile. Spores: bulging Rapidly growing (doubling
Page 27: Clostridium perfringens The agent of - Gangrene - Food poisoning Bacteria features: GPB, Capsulate, non-motile. Spores: bulging Rapidly growing (doubling
Page 28: Clostridium perfringens The agent of - Gangrene - Food poisoning Bacteria features: GPB, Capsulate, non-motile. Spores: bulging Rapidly growing (doubling
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Anaerobic cellulitisAnaerobic cellulitis• This is infection of the dermis and

subcutaneous tissue.

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TreatmentTreatment- Antibiotic trapy: Penicillin- Surgery (Ampotasion): Wounds

should be debrided- H2O2- Hyperbaric oxygen therapy (HBOT) - Antitoxin (polyvalent against

different sub-species.)

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Page 34: Clostridium perfringens The agent of - Gangrene - Food poisoning Bacteria features: GPB, Capsulate, non-motile. Spores: bulging Rapidly growing (doubling
Page 35: Clostridium perfringens The agent of - Gangrene - Food poisoning Bacteria features: GPB, Capsulate, non-motile. Spores: bulging Rapidly growing (doubling
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• Hyperbaric oxygen therapy (HBOT) Hyperbaric oxygen therapy (HBOT) is a medical treatment in which the patient breathes 100% oxygen while inside a pressurized chamber.

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Hyperbaric oxygenHyperbaric oxygen

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Food poisoningFood poisoning

Page 43: Clostridium perfringens The agent of - Gangrene - Food poisoning Bacteria features: GPB, Capsulate, non-motile. Spores: bulging Rapidly growing (doubling

Food poisoningFood poisoning• Soil and food. Survives cooking and grows to large

numbers in reheated food, especially meat.

• Enterotoxin is produced when more than 108 vegetative cells is eaten. The cells convert into spores in GI. Enterotoxin is a part of spore coat.

• Clinical findings: Clinical findings: Incubation: 8-16 hours Symptoms: watery diarrhea, cramps, little

vomiting. Resolves in one or two days.

Page 44: Clostridium perfringens The agent of - Gangrene - Food poisoning Bacteria features: GPB, Capsulate, non-motile. Spores: bulging Rapidly growing (doubling

Treatment and preventionTreatment and preventionof food poisoningof food poisoning

• Treatment: Symptomatic – No antimicrobial drugs

• Prevention Cooking well

Page 45: Clostridium perfringens The agent of - Gangrene - Food poisoning Bacteria features: GPB, Capsulate, non-motile. Spores: bulging Rapidly growing (doubling

Lab diagnosisLab diagnosis• Smear of necrotic tissue and exudate samples:

large positive G+ rods.• Cultured anaerobically I. Blood agarII.Thyoglicolate(identified with fermentation reactions)• Food poisoning: isolation of similar strains in

large numbers from food sources and faeces.

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Clostridium difficileClostridium difficile• GPB • Motile• Long, irregularly (often "drumstick" or

"spindle") shaped cells• Spores: Terminal, bulging• Ubiquitous in nature and especially prevalent

in soil

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TransmissionTransmissionUbiquitous in nature and are especially

prevalent in soil.

Commensal bacterium of the human intestine in 2-5% of the population.

Page 52: Clostridium perfringens The agent of - Gangrene - Food poisoning Bacteria features: GPB, Capsulate, non-motile. Spores: bulging Rapidly growing (doubling

DiseaseDiseaseClostridium difficile infection (CDI)

• Antibiotic-associated diarrhea (25% of antibiotic-related diarrhea)

• Antibiotic-associated pseudomembranous colitis

• Nosocomial infection

Page 53: Clostridium perfringens The agent of - Gangrene - Food poisoning Bacteria features: GPB, Capsulate, non-motile. Spores: bulging Rapidly growing (doubling

Determinants of pathogenicityDeterminants of pathogenicity

• Enterotoxin (toxin A) and Cytotoxin (toxin B) (heat and acid-labile proteins)

Both found in patients’ feces with pseudomembranous colitis.

Attach to the intestinal epithelial cells at the microvilli level and are responsible for the diarrhea and inflammation.

Page 54: Clostridium perfringens The agent of - Gangrene - Food poisoning Bacteria features: GPB, Capsulate, non-motile. Spores: bulging Rapidly growing (doubling

Pathogenesis of C. difficile:Pathogenesis of C. difficile: Pseudomembranous colitisPseudomembranous colitis

• A severe infection of the colon, often resulting from eradication of the normal gut flora by antibiotics.

• Antibiotic (Clindamycin and Ampicillin) supress drug-sensitive normal flora, allowing C. difficile.

Page 55: Clostridium perfringens The agent of - Gangrene - Food poisoning Bacteria features: GPB, Capsulate, non-motile. Spores: bulging Rapidly growing (doubling

Pseudomembranous colitisPseudomembranous colitis (PMC) (PMC)

• Acute colitis characterized by the formation of an adherent inflammatory membrane overlying sites of mucosal injury.

• Exudates composed of fibrin, mucin, bacteria and polymorphonuclear leukocytes attach to the mucosal surface.

Page 56: Clostridium perfringens The agent of - Gangrene - Food poisoning Bacteria features: GPB, Capsulate, non-motile. Spores: bulging Rapidly growing (doubling

Clinical findings

• Diarrhea• Pseudomembranes (yellow-white plaques)

on the colonic mucosa.• Visualised by colonoscopy.

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Lab diagnosisLab diagnosis• Culture and isolation of C. difficile on Blood agarBlood agar

• Identification of toxins by specific antibody using Enzyme immunoassays (EIAs) for the detection of toxins A and B in fecal material.

• Identification of exotoxins by cell cultures: Cytopatic effects (CPEs)

• PCR

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TreatmentTreatment• Withdrew the antibiotics Clindamycin

and Ampicillin.

• Oral metronidazole or vancomycin instead along with fluids.