[Micro] clostridia
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Clostridia species are gram-positive, motile rods that are saprophytic in soil and the guts of animals and humans. They can cause diseases like botulism, gas gangrene, pseudomembranous colitis, and tetanus. Clostridium botulinum produces a potent neurotoxin that causes botulism. The toxin binds motor neurons and prevents the release of acetylcholine, causing flaccid paralysis. Tetanus is caused by Clostridium tetani toxin which prevents inhibitory signals in the central nervous system, causing painful muscle spasms. Clostridium difficile can cause antibiotic-associated diarrhea by producing toxins that damage the intestinal lining.
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[Micro] clostridia
- 1. CLOSTRIDIA SPECIES AnO2, Gram +, motile rods Saprophytes…soil, gut animals/humans
- 2. organisms • Botulism • Gas gangrene • Pseudomembranous colitis • Tetanus
- 3. Morphology/ culture • Spores: wider than diameter of bacillus • Position: centre, terminal, subterminal • Motile: peritrichous flagellae • CULTURE: AnO2, BA • COLONIES: SMALL, LARGE, HEMOLYSIS • GROWTH: Sugar fermentation, protein digestion, milk stormy fermentation ie clot torn by gas • ENZYME : Different
- 4. CLOSTRIDIUM BOTULINUM • Botulism • World-wide • Soil, rarely animal feces • Spores: heat resistant 100 C many hours • R decreased by acid, salt • TOXIN: Released on growth, autolysis • Ag types: A-G • Human pathogen ; A,B,E
- 5. TOXIN ….CONTD • A……FOODS • E…..FISH • C ….BIRDS • D…..MAMMALS • MOL. WT: 150,000( 100,000 &50,000 fragments by s-s bond • Absorbed by gut • Bind to pre synaptic memb of motor neurons • Cranial nerves, PNS
- 6. toxin • Neuron proteins( SNARE) inhibit release of Ach at synapse • Lack of muscle contraction….paralysis • Most lethal toxin: 1-2ug • Destroyed by heat at 100 for 20min
- 7. PATHOGENESIS 1. FOOD: Intoxication; not infection • Canned, alkaline, eaten raw, • Vacuum packed, spiced, smoked • Spores: germinate, release toxin in AnO2 • Ach release blocked and FLACCID PARALYSIS 2. WOUND: A&B
- 8. CLINICAL FINDING • Food ingestion…..18-24 hrs • Visual disturbance: in-coordination of eye muscle, double vision • Speech difficulty • Swallowing difficulty • Bulbar paralysis • Death, respiratory/cardiac arrest • Pt conscious till death • Fever; absent, no anti-toxin in blood if recovery
- 9. INFANT BOTULISM • Common in US • Food ingestion • Floppy baby: poor feed, weak, paralysis • Honey; vehicle • Feces: CB, toxin • Serum: none
- 10. Lab diagnosis TOXIN: in serum & food left overs Mice: I/P injection; death Ag type: neutralization in mice CULTURE: Food remains test for toxin; RIA, Hagglut. Infant: bowel, toxin & CB; not in serum
- 11. TREATMENT 1. TRIVALENT ANTI-TOXIN • 3 potent anti-toxins; A,B,E • Prepared in Horses • GIVE I/V 2.Mechanical respiration • Mortality brought down INFANTS: • Recover on support • Anti-toxin given
- 12. EPIDEMIOLOGY • SOIL; vegetables, fruits, • Canning; destroy spores, • boil ; 20 minutes before use • Home canning: beans, corn, peppers, olives, peas, fresh fish, smoked fish • TOXIC: spoiled, ranscid, swelled cans • Toxoids: for cattle • Bioterrorism, warfare
- 13. CLOSTRIDIU TETNAI • Soil • Animal feces • O Ag –same • Flagellar- several • Toxin- same, neurotoxin • TOXIN: Tetanospasmin • MW: 1,50,000(100,000 & 50,000); s-s bond • Motor neurons: Binds pre-synaptic membranes • Retrograde axonal movement to neurons SC, B STEM
- 15. • Toxin moves to inhibitory cells, degrades synaptobrevin, a protein that docks vesicles to pre synap memb. • Release of inhibitor is blocked & cells are not inhibited • Hyper-reflexia & muscle spasm ensues • V. small amounts may be lethal
- 16. PATHOGENESIS • SITE: devitalized tissue, AnO2 • Wound • Umbilical stump • Burn • Injury • Surgical suture • TOXAEMIA, little infection • Spore germination; necrotic tissue, Calcium salts,pyogenic infection; ow oxid-reduction • Toxin released, travels & fixes to receptors in CNS
- 17. CLINICAL FINDINGS • Incubation: 4-5 days….weeks • Tonic contraction of voluntry muscles of • Injury • Jaw…lock jaw • Tetanic spasm on external stimulus • Painful • Conscious • Death…resp failure • High mortality
- 19. DIAGNOSIS • H/O injury • d/d strychnine poisoning • Culture • Anti-toxin given PREVENTION: • Active immunization by TOXOID • CARE OF WOUND WITH SOIL CONTAMINATION • PROPHYLACTIC USE OF ANTI-TOXIN • PENCILLIN
- 20. 1.Human anti toxin or Tetanus immune globulin • 250-500 units I/M….2-4 weeks OR • 3000-10,000units to N unbound toxin • Neutralizes toxin fixed to nervous tissue 2.Active immunization also done Muscle relaxants, sedation Assisted ventilation Surgical debridement Pencillin; prevent CT growth & super added infection Immunized individual: TOXOID; recall injection
- 21. CONTROL • Preventable • Universal Immunization: TOXOID • Formalin treat toxin; concentrate • AL –salt adsorbed toxoids usedchild: 1 st year • 3 injections • Booster: after 1 year • then before school entry • 10 years apart • Maintain serum level at 0.01units/ml • Children : DPT
- 22. clostridia • C perfringens • C novyi • C histolyticum • C septicum
- 23. CLOSTRIDIA PERFRINGENS • INVASIVE INFECTION • Myonecrosis • Gas gangrene • TOXINS: • Spreading infection • Lethal, necrotizing, hemolytic • Alpha toxin: lecithinase; splits CM lecithin • Theta toxin: hemlytic, necrotic • DNAse, hyalouronidase: digest collagen of s/c, muscle
- 24. • FOOD POISONING: ENTERO-TOXIN, meat dishes 108cells ingested, diarrhea in 6-18 hrs; hyper-sec in jej, ileum, self limiting • Rarely n,v, fever • PATHOGENESIS • TRAUMA • Spore contamination….soil/intestine • Spore…germinate in low o-r potential; CELLS MULTIPLY • CHO fermented,gas produced,blood supply obst
- 25. • Spreading factors released • Tissue necrosis increases, increased bacterial growth, hemolytic anemia, toxaemia, death • Gas gangrene, myonecrosis, mixed infection occurs by toxigenic clostridia • Proteolytic clostridia, cocci, gram negative organisms • Genital tract: 5% femalesabortion associated • C sordelli: endometrial infection, • bacteraemia if neoplasia • C perferingens type C: children necrotizing enteritis; TOXOID helps
- 26. CLINICAL FINDING CONTAMINATION…..WOUND, UTERUS….1-3 days crepitations in S/C tissue, muscle…foul discharge… necrosis..fever, hemolysis, toxaemia, shock..death Cellulitis, fascitis TREATMENT: Amputation Anti-biotic Food poisoning; spores germinate in warmed meat dishes, toin, diarrhea lasts 1-2 days
- 27. LAB TESTS SPECIMEN: • Wound • Pus • Tissue • Gram’s: + rods, spore? • Met glucose medium • BA AnO2: colonies;heolysis, I/D by biochemicals • Milk: clot-torn by gas in24 hrs • Egg-yolk medium: lecitjinase ppt around colonies • Toxin checked; neutralized by anti-toxin
- 31. TREATMENT • Surgical debridement: prompt, extensive • AB; Pencillin • Hyperbarric oxygen • Anti-toxins as conc. Immune globulin • Food poisoning: symptomatic managemnt • PREVENTION: • EARLY, ADEQUATE CLEANSING • SURGICAL DEBRIDEMENT • AB. PENCILLIN
- 32. CLOSTRIDIUM DIFFICILE • DIARRHEA: AB given esp AMP, CLINDAMYCIN • C difficile toxin in stool • Endoscopy: pseudomembrane • localized…… plaques, microabscesses • SYMPTOMS: Diarrhea; watery, bloody • cramps • fever, leukocytosis • T/M: discontinue AB • Start V an, Metronidazole
- 33. PATHOGENESIS • AB; R C difficile proliferate • Toxins: A….enterotoxin, cytotoxin bind to brush border receptors • Toxin B: cytotoxin • Toxins in stool
- 34. AB –associated diarrhea • Mild…moderate • Less severe than pseudoMC • 25%.....associated with C difficile