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Clostridia.Clostridia.Clostridia.Clostridia.Clostridia.Clostridia.Clostridia.Clostridia.
- 1. Gram Positive Rods .Spore forming .Non Spore forming
- 2. Gram Positive Rods .Spore forming Bacillus------ Aerobic Clostridium--Anaerobic
- 3. Clostridia
- 4. Four important: Clostridium tetani Clostridium botulinum Clostridium perfringens Clostridium difficile
- 5. Clostridium tetani--Tetanus Transmission: Spores in soil .Portal of entry- usually wound site, Nail penetrating foot, Skin popping .Neonatal tetanusorg enters through contaminated umbilicus or circumcission wound
- 6. Pathogenesis Contamination of damaged devitalized tissue(wound umbilical stump) with spores Germination of spores release of tetanospasmin (an exotoxin polypeptide) produced by vegetative cells at wound site Carried intra axonally to CNS (retrograde axonal transport ) or blood stream Binds to ganglioside receptors & blocks release of inhibitory mediators (Glycine &GABA) at spinal synapses(Cleaves the proteins involved in mediator release) Tetanus toxin has only one antigenic type
- 8. C/F Tetanus Strong muscle spasms (Spastic paralysis) Lock jaw Risus sordonicusA grimace OpisthotonosPronounced arching of back Respiratory failure Patient is fully consciousPain is intense during spasms High mortality
- 9. Lab Diagnosis No microbiologic or serologic diagnosis Prevention: More important than the treatment Prevented by Toxoid in combination with diphtheria toxoid & pertusis vaccine (DPT) .Cleaning & debridement of wound and proper care of wound thereafter Toxoid booster dose with immune globulin (antitoxin) .Penicillin G
- 11. Sporeswidespread in soil contaminate vegetables & meats especially when canned, vaccum-packed without proper sterilization. Anaerobic environment favours germination Toxin produced within canned food
- 12. Botulinal toxin along with tetanus toxin, is among the most toxic substances known (fatal dose 0.1- 1袖g) When absorbed from gut it is carried via blood stream to peripheral nerve synapses and primarily affects cholinergic nervous system blocking the release of Acetylcholine, blocking nerve impulse Toxin has 8 immunologic types (A-H) A,B,EHuman illness Botox
- 14. C/F Descending weaknes/paralysis with Diplopia, Dysphagia,fever is rare. Resp. muscle failure. V/S Guillain-Barre syndrome ascending paralysis
- 15. Lab Diagnosis Cultured on cooked meat anaerobically but Commonly not cultured Mouse protection test demonstrates botulism toxin (mice will die with clinical sample if not protected with antitoxin) Treatment : Trivalent antitoxin(A,B,E) Prevention: Proper sterilizatin of canned & vacuum-packed food
- 16. Clostridium perfringens (C.welchi) .Gas gangrene .food poisoning
- 17. Gas Gangrene (Myonecrosis, necrotizing fascitis): Transmission: Spores present in soil Vegetative cellsNormal flora of colon & vagina Associated with War wounds , Road traffic accidents & septic abortions
- 18. Pathogenesis Traumatized tissue (muscle)site for org. growth Produces many toxins esp Lecithinase --damages cell membranes (RBCs too)---Hemolysis Degradative enzymes produce gas in tissues
- 19. C/F Pain, edema, cellulitis & gangrene in wound Crepititions in tissue due to gas produced HemolysisJaundice Shock, Death
- 20. Lab Diagnosis Large gram positive bacilli on gram staining Cultured anaerobically Sugar fermentation tests Egg yolk agar demonstrates the presence of lecithinase (seen as opacity in the medium due to break down of lecithin)Nagler reaction
- 21. Food poisoning: Spores in soil- can contaminate food Grow mainly in reheated foods esp meat dishes A normal flora in the colon Its enterotoxin acts on small intestine (where it is not flora) & causes diarrhea Super Ag as that of staph aureus
- 22. C/F Incubation period 8-16 hrs Watery diarrhea with cramps Lab Diagnosis: Not done Treated symptomatically. No antibiotic given
- 23. 0 Clostridium difficile Causes .Pseudomembranous colitis (Antibiotic associated) Nosocomial diarrhea- Most common cause
- 24. Tansmission &Pathogenesis In general population3 % In hospitalizesd pt------30% Transmitted by fecal oral route Drug sensitive flora suppressed by antibiotics allowing C.difficile to multiply Has Exotoxin with A & B (glucosylate) causing depolarization of actin & damage, apoptosis death of enterocytes
- 25. Drugs: Clindamycin-1st antibiotic to be associated Most commonly 3rd generation cephalosporins Ampicillin & flouroquinolones too Cancer chemotheraputics
- 26. C/F Diarrhea associated with pseudomembranes on colonic mucosa Non bloody Neutrophils may be present Fever, abdominal pain Sigmoidoscopy Presence of toxin can be detected
- 27. Lab diagnosis To detect presence of Exotoxins in pt. stool 2 tests .ELISA using antibody to exotoxin .Cytotoxicity test-Human cells in culture are exposed to the exotoxin in stool & death of cells observed .PCR
- 28. Treatment & Prevention: .Withdrawing of causative antibiotic .Give oral metronidazole or vancomycin .Surgical removal of colon in Severe cases Fecal Bacteriotherapy- Administering bowel flora from a normal individual by enema or nasodeudenal tubeReplaces the C.difficile