Clostridium species - Microbiology


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Clostridium species - Microbiology

  1. 1. College Of Dentistry - Mosul University
  2. 2. Clostridium Gram-positive . obligate anaerobes capable of producing endospores which protect them in harmful environment . Individual cells are rod shaped. The spores are usually wider than the rods, and are located terminally or sub terminally. Most clostridia are motile by peritrichous flagella.while others have a capsule like Clostridium.perfringens Characteristics College Of Dentistry - Mosul University 2
  3. 3. Clostridium consists of around 100 species that include common free-living bacteria as well as important pathogens There are five main species responsible for disease in humans. College Of Dentistry - Mosul University C. perfringens: gas gangrene; food poisoning C. tetani: tetanus C. botulinum: botulism C. difficile: pseudomembranous colitis C.Sordellii : can cause a fatal infection in exceptionally rare cases after medical abortions
  4. 4. The shape an position of spores varies in different species and is useful the identification of Clostridia *Central in Cl.bifermentans *Sub terminal in Cl.perfringens *Oval or terminal in Cl.tertium *Spherical and terminal giving drum stick appearance in Cl.tetani College Of Dentistry - Mosul University 4
  5. 5.  C. perfringens is a relatively large Gram- positive short fat bacilli with blunt ends. It is capsulate and non-motile. Anaerobic. It grows quickly on laboratory media on blood agar ( B – Haemolytic ) College Of Dentistry - Mosul University 5
  6. 6.  Liquid medium for cultivation cooked meat broth  Thiglyclolate broth  CMB contain unsaturated fatty acids which take up oxygen College Of Dentistry - Mosul University 6
  7. 7. Clostridium. perfringens Culture & identification College Of Dentistry - Mosul University 7
  8. 8. It distinguish between different species of bacteria. The lactose (milk sugar), litmus (pH indicator), and casein(milk protein) contained within the medium can all be metabolized by different types of bacteria. Milk is the first substrate used to maintain bacteria, this test allows for accurate depiction of bacterial types. The addition of litmus, other than explaining the pH type, acts as an oxidation-reduction indicator. The test itself tells whether the bacterium can ferment lactose, reduce litmus, form clots, form gas, College Of Dentistry - Mosul University
  9. 9.  This test is done to detect the lecithinase activity  The M.O is streaked on the medium containing egg yolk (contains lecithin)  The plate is incubated anaerobically at 37 C for 24 h  Colonies of Cl. perfringens are surrounded by zones of turbidity due to lecithinase activity and the effect is specifically inhibited if Cl. perfringens antiserum containing antitoxin is present on the medium  ` College Of Dentistry - Mosul University 9
  10. 10. C. perfringens Nagler Reaction NOTE: Lecithinase (α-toxin; phospholipase) hydrolyzes phospholipids in egg-yolk agar around streak on right. Antibody against α-toxin inhibits activity around left streak. College Of Dentistry - Mosul University 10
  11. 11. College Of Dentistry - Mosul University Positive Nagler Reaction Procedure of Nagler Reaction
  12. 12. College Of Dentistry - Mosul University 12 Anaerobic Jar
  13. 13. College Of Dentistry - Mosul University 13
  14. 14.  The organisms associated with gas gangrene attack soft tissues by producing toxins and aggressins, and some strains of the bacteria produce enterotoxins and cause food poisoning College Of Dentistry - Mosul University 14
  15. 15.  If there are pieces of necrotic tissue in the wound, small pieces should be transferred aseptically into a sterile screw-capped bottle and examined immediately by microscopy and culture. Specimens of exudate should be taken from the deeper areas of the wound where the infection seems to be most pronounced. College Of Dentistry - Mosul University 15
  16. 16.  Virulence factors  toxins –  alpha toxin – causes RBC rupture, edema and tissue destruction  Enterotoxin  collagenase  Hyaluronidase  DNase College Of Dentistry - Mosul University 16
  17. 17. Clostridium tetani Anaerobic bacteria of the genus species Clostridium it is gram positive, slender bacillus and it has spherical terminal spores giving drum stick appearance It is non capsulated & motile with peritrichus flagella It produces a potent biological toxin, tetanospasmin, and is the causative agent of tetanus a disease characterized by painful muscular spasms that can lead to respiratory failure and, in up to 40% of cases, death. College Of Dentistry - Mosul University
  18. 18.  An infectious disease caused by contamination of wounds from the bacteria Clostridium tetani, or the spores they produce that live in the soil, and animal feces  Infection follows when spores  become activated and develop  into gram-positive bacteria that multiply  and produce a very powerful toxin (tetanospasmin) that affects the muscles. College Of Dentistry - Mosul University
  19. 19.  Tetanus spores are found throughout the environment, usually in soil, dust, and animal waste.  Tetanus is acquired through contact with the environment; it is not transmitted from person to person. College Of Dentistry - Mosul University
  20. 20.  The usual locations for the bacteria to enter the body:  Puncture wounds (such as those caused by rusty nails, splinters, or insect bites.)  Burns, any break in the skin, and IV drug access sites are also potential entryways for the bacteria. College Of Dentistry - Mosul University
  21. 21. 1. It inhibits the release of acetylcholine thus it interferes with neuromuscular transmission.  2. Inhibition of postsynaptic spinal neurons by blocking the release of an inhibiting mediator College Of Dentistry - Mosul University
  22. 22.  Gram +ve stains grow on blood agar media aerobically  Inoculation of culture in to 2 mice one is protected with anti-toxin and the other is unprotected (dies with typical tetanic spasms ) College Of Dentistry - Mosul University
  23. 23. College Of Dentistry - Mosul University
  24. 24. Clostridium difficile
  25. 25. "C. diff", is a species positive-Gramof of the genusbacteria thatClostridium causes diarrhea and other intestinal disease when competing bacteria are wiped out by antibiotics.
  26. 26. Most common cause of nosocomial diarrhea. Rate and severity of C. difficile-associated diarrhea (CDAD) increasing. Clostridium difficile is a bacterium that can cause symptoms ranging from diarrhea to life-threatening inflammation of the colon. Illness from C. difficile most commonly affects older adults in hospitals or in long term care facilities and typically occurs after use of antibiotic medication
  27. 27. characteristic features: Clostridia are anaerobic, spore- forming rods (bacilli).
  28. 28. C. difficile bacteria can be found throughout the environment — in soil, air, water, and human and animal feces. A small number of healthy people naturally carry the bacteria in their large intestine. But C. difficile is most common in hospitals and other health care facilities, where a much higher percentage of people carry the bacteria.
  29. 29. Reservoir Infectious Agent C.difficile Means of Transmission Portal of entry Susceptible Host Chainof infection Bowel and Contaminated environment Contact transmission from contaminated hands, equipment or the environment Faecal/Oral >65 years History of antibiotic use Recent received healthcare Underlying conditions Abdominal surgery Weakened immunity
  30. 30. Disruption of normal colonic flora Colonisation with C. difficile Production of toxin A +/- B Mucosal injury and inflammation
  31. 31. Toxigenic strains produce 2 major toxins: toxin A (enterotoxin) toxin B (cytotoxin) Neutralised by C. sordellii antitoxin
  32. 32. Watery diarrhea three or more times a day for two or more days Mild abdominal cramping and tenderness Watery diarrhea 10 to 15 times a day Abdominal cramping and pain, which may be severe Fever Blood or pus in the stool Nausea Dehydration Loss of appetite Weight loss
  33. 33. Pseudomembraneous colitis Perforation of the colon Sepsis Death
  34. 34. The Specimen Fresh is best (test within 2 hours) Liquid or loose, not solid If unable to test within 2 hours, refrigerate at 4 C for up to 3 days Freeze at -70 C (not -20 C) if testing will be delayed Specimen quality will influence test results
  35. 35. Endoscopy (pseudomembranous colitis) Culture Cell culture cytotoxin test EIA toxin test PCR toxin gene detection
  36. 36. preventation
  37. 37. Note : alcohol does not kill C. difficile spores, use of soap and water is more efficacious
  38. 38. Gram positive Obligate anaerobic bacillus Spores Resistant to heat, light, drying and radiation Specific conditions for germination Anaerobic conditions Warmth (10-50oC) Mild alkalinity
  39. 39. Ingestion Organism Spores Neurotoxin Wound contamination Inhalation Person-to-person not documented
  40. 40. Three forms Foodborne Wound Infant All forms fatal and a medical emergency Incubation period: 12-36 hours
  41. 41. The symptoms of botulism are similar to those of Guillain-Barré syndrome, stroke, and myasthenia gravis. As a result, botulism is probably substantially under-diagnosed. Serum electrolytes, renal and liver function tests, complete blood tests, urinalysis, and electrocardiograms will all be normal unless secondary complications occur.
  42. 42. The incubation period varies according to the mode of transmission, rate of absorption of the toxin, and the total amount and type of toxin. Foodborne botulism usually takes 24-36 hours to manifest itself. Wound botulism often takes 3 or more days to appear. Inhalation botulism has occurred very rarely, but incubation times may range from several hours to perhaps days, again depending upon the type and amount of toxin inhaled.
  43. 43. All four types of botulism result in symmetric descending flaccid paralysis of motor and autonomic nerves always beginning with the cranial nerves. These symptoms are preceded by constipation in cases of infant botulism. Symptoms include: Double or blurred vision Drooping eyelids Dry mouth Difficulty Swallowing Muscle weakness
  44. 44. If left untreated symptoms may expand to include paralysis of respiratory muscles as well as the arms and legs. Asphyxiation due to respiratory paralysis is the most common cause of death in botulism cases.
  45. 45. Proper food preparation is one of the most effective ways to limit the risk of exposure to botulism toxin. Boiling food or water for ten minutes can eliminate some strains of Clostridium botulinum as well as neutralize the toxin as well. However, this will not assure 100% elimination. Limiting growth of Clostridium botulinum and the production of botulism toxin is an alternative to their outright destruction.
  46. 46. Now manufactured under the name ―Botox‖ Experimentally used for treating migraine headaches, chronic low back pain, stroke, cerebral palsy, and dystonias (neurologic diseases involving abnormal muscle posture and tension) Frequent injections allows an individual to develop antibodies Studies carried out to determine feasibility of other strains of BoNT BoNT B manufactured for treatment of cervical dystonia in 2000 as ―Myobloc‖
  47. 47. Botox injection patient 13 weeks after injection Sadick, N. and A.R. Herman (2003). “Comparison of Botulinum Toxins A and B in the Aesthetic Treatment of Facial Rhytides.” Dermatologic Surgery 29:340-347.