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Clostridium.pptx
- 1. CLOSTRIDIUM Dr. Rachana Choudhary Department of Microbiology Shri Shankaracharya Mahavidyalaya, Junwani Bhilai (C.G.)
- 2. Synopsis •Introduction •History •Classification •Some common pathogenic bacteria 1. Clostridium botulinum 2. Clostridium tetani 3. Clostridium perfringens •Conclusion •Reference
- 3. INTRODUCTION The genus Clostridium consists •Gram positive •Anaerobic, spore bearing •Straight or slightly curved rods •Saprophytes •Some are commensals of the animal & human gut. •Disease Caused Gas gangrene, Tetanus, Botulism Fig:- Clostridium
- 4. HISTORY •5th Century BC: Hippocrates first described the disease •1884: Carle and Rattone discovered the etiology . •Produced tetanus by injecting pus from a fatal human case •1897: Nocard demonstrated the protective effect of passively transferred antitoxin used in WWI •1924: Descombey developed tetanus toxoid for active immunization used in WWII
- 5. CLASSIFICATION Position of spore Both proteolytic & saccharolytic Slightly proteolytic / Saccharolytic / Neither proteolytic nor saccharolytic Proteolytic Saccharolytic Central or sub- terminal Oval & terminal Spherical & terminal Cl.bifermentans Cl.botulinum Cl. histolyticum Cl. sordelli Cl. sporogenes ___ ___ Cl. perfringens Cl. septicum Cl. chuvoei Cl. novyi Cl. difficile ___ Cl. fallax ( S/nPro.) Cl. botulinum ( “=“ ) Cl. tertium Cl. tetani A Morphological & Biochemical Classification of Clostridia
- 6. SOME COMMON PATHOGENIC BACTERIA • Cl. Perfringens • Cl. botulinum • Cl. tetani They are dealt as following Introduction Morphology Classification Cultural characteristics Resistance Toxins Pathogenicity Treatment & Diagnosis Prevention
- 7. 1. Clostridium perfringens Fig:- Cl. Perfringens Introduction:- • Formerly known as Cl. welchii • Gram- positive, anaerobic, spore forming bacteria • Present in – decaying vegetation, marine sediment, intestinal tract human & vertebrates, soil. Morphology :- • Large rod shape, about 4- 6µm×1µm, capsulated, non motile, filamentous, spores are central & sub terminal.
- 8. Classification:- Based on production of toxins. Type-A Type-B Type-C Type-D Type-E Cultural characteristics :- • It is an anaerobe but can also grow under micro aerophilic condition. • pH range - 5.5-8.0 • Temp. range - 20ºC–50ºC • Media – Robertson’s cooked meat medium & blood agar. • Resistance :- • Spores destroyed - 5 min. • Strain, Type-A & Type-C resist boiling 1-2 hour.
- 9. Toxins:- •Cl. perfringens , forming at least 12 distinct toxins. •The 4 major toxin’s – α, β, ε & iota are responsible for pathogenicity. Alpha toxin – causes RBC rupture and tissue destruction. Enterotoxin is heat labile toxin produced in colon → food poisoning Pathogenicity:- •Cl. perfringens produce following human infections – gas gangrene, food poisoning, necrotising entritis etc. •It produce Enterotoxin •Incubation: 1-7 days after infection.
- 10. Enterotoxin •Stomach acids initiate spore germination •When the cell lyses, it releases mature endospores •Spores bind to intestinal epithelial cells and induce intestinal tissue damage •Usually symptoms occur within 6-24 hours of ingestion and can last ~24 hours
- 11. Pathogenicity Fig:- Action of Alpha toxin of Cl. perfringens
- 12. Treatment Prevention •Handling foods properly, especially meats •Use of correct temperatures when cooking and cooling food •165° F kills bacteria,Must be cooled quickly and reheated to 165° F again •Maintaining raw meat at very low temperatures (<40° F) •Depends on toxicity and type of strain ingested •For Animals: Not much can be done once spores are Ingested •For Humans: Penicillin and other antibiotics are used for gas gangrene and wound infections. • Surgery is used for cases in which severe tissue damages occur • Keep hydrated
- 13. 2. Clostridium botulinum Fig:-Clostridium botulinum Introduction:- • A gram-positive, anaerobic bacilli. • Spore forming. • Toxin forming. • Heat sensitive. • Prefers low acid environment. • Cause Botulism disease. Morphology :- • Rod shape,5µm ×1µm • Motile, noncapsulated • Spores subterminal
- 14. Classification • 8 types of Cl. botulinum on the basis of toxins. • Type A, B, C1, C2, D, E, F, G. Cultural characteristics • Strict anaerobic • Optimum temp. for growth - 35ºC • Some may grow even 1–5ºC. • Spores produced – Glucose gelatin media (20–25ºC). Resistance • Spores are heat & radiation resistant –several hours at 100ºC for upto 10 min at 120ºC. • Spores of nonproteolytic types of B, E and F are much less resistant to heat.
- 15. Toxin:- •Exotoxin produced- responsible for pathogenicity •librated during growth. •Seven types of toxins (A-G). •Antigenic (light and heavy chain). •Environmental survival. (Inactivated by heat 100ºC for 20 min ). •Most potential biological warfare agents. • Lethal dose= 1-2 g . Pathogenicity :- •Cl.botulism is noninvasive and virtually noninfectious. •Pathogenicity – due to action of toxin ( neurotoxin ). •Cause “Botulism” in human.
- 16. Fig :- Mechanism of Botulinum toxin
- 17. Prevention •Proper food handling and preparation •80°C for 10 minutes or longer •Manufacturers use thermal processes designed to destroy spores •Processors add salt or nitrites to reduce growth Diagnosis and Treatment Electrodiagnostic testing = repetitive nerve stimulation Test serum or feces of the patient for the toxin Mouse neutralization test 48 hours to complete 5-7 days to culture specimens Neutralized by an antitoxin - only in circulation
- 18. 3.Clostridium tetani Fig:- Clostridium. tetani Introduction:- • Cl. tetani is the causative organism of tetanus. • Gram positive, straight, slender rod with rounded ends • Endospore Forming • Fermentative • Obligate anaerobe • Motile by peritrichous flagella Morphology:- • Slender rod shape, about 14 µm×0.5µm • Spores – terminal, spherical in shape • Like drumstick
- 19. Classification:- Ten serological types have been recognised based on agglutination (types I to X ) Cultural characteristics:- •Obligatory anaerobe that grows only in the absence of oxygen. •Optimum growth temp.-37ºC & pH – 7.4 Resistance:- •The resistance of tetanus spores to heat appears to be subjected to strain differences •Most are killed by boiling for 10-15 min.
- 20. Toxins:- Cl.tetani produce 2 toxins tetanus toxin or tetanospasmin •The second exotoxin produced tetanolysin-function not known. Pathogenicity:- •Not pathogenic to humans and animals by invasive infection but by the production of a potent protein toxin . •It is causative organism of tetanus.
- 21. Mechanism of Cl.tetani toxin (Pathogenicity)
- 22. Transmition • C. tetani can live for years as spores in animal feces and soil. • It enters the human body :- by wound • Tetanus may follow burns, deep puncture wounds, ear or dental infections, animal bites, abortion. • It is the only vaccine-preventable disease that is infectious but not contagious from person to person. Symptoms • Tetanic seizures (painful, powerful bursts of muscle contraction) • if the muscle spasms affect the larynx or chest wall, they may cause asphyxiation • stiffness of jaw (also called lockjaw) • stiffness of abdominal and back muscles • contraction of facial muscles • fast pulse • fever • sweating
- 23. Methods of diagnosis Based on the patient’s account and physical findings that are characteristic of the disease. Diagnostic studies generally are of little value, as cultures of the wound site are negative for C. tetani two-thirds of the time. When the culture is positive, it confirms the diagnosis of tetanus Tests that may be performed include the following: Culture of the wound site (may be negative even if tetanus is present) Tetanus antibody test Other tests may be used to rule out meningitis, rabies, strychnine poisoning, or other diseases with similar symptoms.
- 24. Treatment •If treatment is not sought early, the disease is often fatal. •The bacteria are killed with antibiotics, such as penicillin or tetracycline; further toxin production is thus prevented. •The toxin is neutralized with shots of tetanus immune globulin, TIG. •Other drugs may be given to provide sedation, relax the muscles and relieve pain. •Due to the extreme potency of the toxin, immunity does not result after the disease.
- 25. Prevention •Rigorous hygienic response to injury •Vaccination •First 4 immunization shots (DTP: diphtheria-tetanus- pertussis) given within 2 years •Every 10 years: booster shot
- 26. Conclusion All Clostridium is an anaerobic bacteria found in soils and sediments, especially in areas of pollution, Persists in fecal matter and intestinal tracts of animals and humans. It’s causes different major diseases in humans & animals. Using the correct temperatures in cooking, cooling, or reheating food is crucial to inhibit bacteria growth in food.
- 27. Reference •Book of Microbiology :- R.P. Singh •Textbook of Microbiology :- Ananthanarayan & Paniker’s •Principles of Microbiology (7th edition) :- Prescott.
- 28. THANK YOU