Tetanus Teaching basics by Dr.T.V.Rao MD

Views:
 
Category: Education
     
 

Presentation Description

Tetanus Teaching basics by Dr.T.V.Rao MD

Comments

Presentation Transcript

Clostridium tetani teaching basics Dr.T.V.Rao MD:

Clostridium tetani teaching basics Dr.T.V.Rao MD 8/23/2015 Dr.T.V.Rao MD @ Rao's Microbiology 1

Clostridia: general characteristics:

Clostridia: general characteristics Genus Clostridium contains a large number of gram-positive, spore-forming species, several of which are able to produce disease in humans. Most species are obligate anaerobes, some will grow under microaerophilic conditions. Natural habitat: soil and the intestinal Tract 8/23/2015 Dr.T.V.Rao MD @ Rao's Microbiology 2

History:

History Tetanus was well known to ancient people, who recognized the relationship between wounds and fatal muscle spasms. In 1884, Arthur Nicolaier isolated the strychnine-like toxin of tetanus from free-living, anaerobic soil bacteria. Rosenbach and Kitasato contributed 8/23/2015 Dr.T.V.Rao MD @ Rao's Microbiology 3

Clostridium tetani:

Clostridium tetani Clostridium tetani  is a rod-shaped, anaerobic bacterium of the genus  Clostridium ..  C. tetani  is found as spores in soil or as parasites in the gastrointestinal tract of animals.  C. tetani  produces a potent biological toxin, tetanospasmin, and is the causative agent of tetanus 8/23/2015 Dr.T.V.Rao MD @ Rao's Microbiology 4

Clostridium tetani:

Clostridium tetani Clostridium tetani  is an anaerobic pathogenic bacterium that is primarily found in soil and animal intestinal tracts. Cotton, dust Plaster of Paris Catugut 8/23/2015 Dr.T.V.Rao MD @ Rao's Microbiology 5

Morphology:

Morphology Gram + bacilli 4-8 x 0.5 microns Drumstick appearance Obligatory anaerobe 8/23/2015 Dr.T.V.Rao MD @ Rao's Microbiology 6

Cultural characteristics':

Cultural characteristics' Grows on blood agar with advancing edges In gelatin stab fir tree appearance In Robertson cooked meat medium produces turbidity gas Meat is not digested turns black First α hemolysis followed by β hemolysis 8/23/2015 Dr.T.V.Rao MD @ Rao's Microbiology 7

C. tetani: key characteristics:

C. tetani: key characteristics Large, spore-forming, motile, obligate anaerobic bacillus ( see below ). Ferments: proteins or amino acids. Produces: acetic acid, fatty acids, NH 3 , CO 2 , H 2 , and a strong exotoxin. Tetanospasmin, a powerful neurotoxin 8/23/2015 Dr.T.V.Rao MD @ Rao's Microbiology 8

Resistance of the Clostridium tetani:

Resistance of the Clostridium tetani .Survives boiling upto 3 hours They can not survive autoclaving at 249.8 °F (121 °C) for 20 minutes. The spores are also relatively resistant to phenol and other chemical agents . 8/23/2015 Dr.T.V.Rao MD @ Rao's Microbiology 9

Biochemical reactions:

Biochemical reactions Indole + MR and VP test negative H2 S not produce Nitrites are not reduced Gelatin liqification occurs 8/23/2015 Dr.T.V.Rao MD @ Rao's Microbiology 10

Tetanus etiology:

Tetanus etiology In necrotic and infected wounds, anaerobic conditions will permit germination. Contaminated puncture wounds can be particularly dangerous, especially when a foreign body is present. 8/23/2015 Dr.T.V.Rao MD @ Rao's Microbiology 11

Mode of Transmission - Tetanus:

Mode of Transmission - Tetanus Mode of Transmission: Transmission is primarily by contaminated wounds, Tissue injury( surgery, burns,deep puncture wounds, crush wounds, Otitis media ,dental infection, animal bites, abortion, and pregnancy Incubation Period : 8 DAYS ( 3-21 DAYS) 8/23/2015 Dr.T.V.Rao MD @ Rao's Microbiology 12

Type of Tetanus:

Type of Tetanus Traumatic tetanus Puerperal tetanus Otogenic tetanus Idiopathic tetanus Tetanus Neonatroum 8/23/2015 Dr.T.V.Rao MD @ Rao's Microbiology 13

Tetanus – Toxin oriented disease:

Tetanus – Toxin oriented disease C. tetani  usually enters a host through a wound to the skin and then it replicates. Once an infection is established,  C. tetani  produces two exotoxins, tetanolysin and tetanospasmin.. The genes that produce toxin are encoded on a plasmid which is present in all toxigenic strains, and all strains that are capable of producing toxin produce identical toxin 8/23/2015 Dr.T.V.Rao MD @ Rao's Microbiology 14

Nature of Toxins:

Nature of Toxins C. tetani produces two exotoxins, tetanolysin and tetanospasmin. The function of tetanolysin is not known with certainty. Tetanospasmin is a neurotoxin and causes the clinical manifestations of tetanus. Tetanospasmin estimated Human lethal dose 2.5 ng/kg 8/23/2015 Dr.T.V.Rao MD @ Rao's Microbiology 15

Toxins:

Toxins Hemolysin ( tetanolysin ) Neurotoxin ( Tetanospasmin ) Non spasmogenic toxin Tetanolysin is heat labile and oxygen laible Toxin is responsible for the Tetanus Heat laible inactivated at 65 0 c Mol wt Heavy chain 93,000 Light chain 52,000 bound by disulphide bonds 8/23/2015 Dr.T.V.Rao MD @ Rao's Microbiology 16

Tetanospasmin:

Tetanospasmin Mol wt Heavy chain 93,000 Light chain 52,000 bound by disulphide bonds Human – 130 nanograms Horse and guinea pigs guinea pigs rabbits effected 8/23/2015 Dr.T.V.Rao MD @ Rao's Microbiology 17

Tetanospasmin:

Tetanospasmin Tetanospasmin is distributed in the blood and lymphatic system of the host. The toxin acts at several sites within the central nervous system, including peripheral nerve terminals, the spinal cord, and brain, and within the sympathetic nervous system. 8/23/2015 Dr.T.V.Rao MD @ Rao's Microbiology 18

Tetanospasmin:

Tetanospasmin The toxin is taken up into within the nerve axon and transported across synaptic junctions, until it reaches the central nervous system, where it is rapidly fixed to gangliosides at the presynaptic junctions of inhibitory motor nerve ending 8/23/2015 Dr.T.V.Rao MD @ Rao's Microbiology 19

Pathogenicty:

Pathogenicty The spores germinate in reduced oxygen potential devitalized tissues, presence of foreign bodies Motor neurons absorb Spread Intraaxonally to CNS Avidly fixed to gangliosides of gray matter 8/23/2015 Dr.T.V.Rao MD @ Rao's Microbiology 20

Slide21:

Mechanism of Action of Tetanus Toxin 8/23/2015 Dr.T.V.Rao MD @ Rao's Microbiology 21

Tetanospasmin:

Tetanospasmin Resembles strychnine blocks synaptic inhibition in the spinal cord At inhibitory terminals that use glycine and GABA as neurotransmitters Toxin acts presynaptically unlike styrchnine post synaptically Muscle spasms of agonists and antagonists 8/23/2015 Dr.T.V.Rao MD @ Rao's Microbiology 22

How Toxin acts:

How Toxin acts The toxin, by blocking the release of inhibitors, keeps the involved muscles in a state of contraction and leads to spastic paralysis , a condition where opposing flexor and extensor muscles simultaneously contract. Death is usually from respiratory failure. 8/23/2015 Dr.T.V.Rao MD @ Rao's Microbiology 23

Clinical manifestations:

Clinical manifestations The clinical manifestations of tetanus are caused when tetanus toxin blocks inhibitory impulses, by interfering with the release of  neurotransmitters , including  glycine and gamma-aminobutyric acid. This leads to unopposed muscle contraction and spasm. 8/23/2015 Dr.T.V.Rao MD @ Rao's Microbiology 24

Tetanus:

Tetanus Involves somatic musculkar system Injuries Punctured wound Surgery Otitis media Septic abortion Cow dung applications Ear boring circumcision Incubation 2 days to weeks Average 6 12 days 8/23/2015 Dr.T.V.Rao MD @ Rao's Microbiology 25

Slide26:

8/23/2015 Dr.T.V.Rao MD @ Rao's Microbiology 26

Opisthotonus :

Opisthotonus   8/23/2015 Dr.T.V.Rao MD @ Rao's Microbiology 27

Slide28:

Photo Courtesy of U.S. Centers for Disease Control and Prevention 8/23/2015 Dr.T.V.Rao MD @ Rao's Microbiology 28

Tetanus symptoms & signs:

Tetanus symptoms & signs Characteristic features are  risus sardonicus   (a rigid smile),  trismus  (commonly known as "lock-jaw"), and opisthotonus   (rigid, arched back). 8/23/2015 Dr.T.V.Rao MD @ Rao's Microbiology 29

Slide30:

Risus Sardonicus in Tetanus Patient 8/23/2015 Dr.T.V.Rao MD @ Rao's Microbiology 30

Laboratory Diagnosis of Tetanus:

Laboratory Diagnosis of Tetanus 8/23/2015 Dr.T.V.Rao MD @ Rao's Microbiology 31

Laboratory Diagnosis:

Laboratory Diagnosis Clinical diagnosis most important in management Microscopy Culture Animal Inoculation Microscopy not reliable 8/23/2015 Dr.T.V.Rao MD @ Rao's Microbiology 32

Culture:

Culture Done on Blood agar One half of plate spreads to other half after 1 – 2 days of incubation anerobically Three tubes of cooked meat broth inoculated 1 tube 80 0 c for 15 mt 2 tube 80 0 c for 5 mt 3 tube unheated All are incubated at 37 0 c upto 4 days Subcultured 8/23/2015 Dr.T.V.Rao MD @ Rao's Microbiology 33

Slide34:

Clostridium tetani Gram Stain Round terminal spores give cells a “drumstick” or “tennis racket” appearance. 8/23/2015 Dr.T.V.Rao MD @ Rao's Microbiology 34

Showing spores and Grwoth on Blood Agar plate:

Showing spores and Grwoth on Blood Agar plate 8/23/2015 Dr.T.V.Rao MD @ Rao's Microbiology 35

Toxigenicty tests:

Toxigenicty tests In a plate of Blood divided into 2 halves first half incorporated with 1500 / ml of antitoxin Hemolysis without antitoxin Bacteria grown in Robertson cooked meat medium inoculated into tail of a mice A 2 nd animal injected with tetanus antitoxin 1000 units an hour earlier the test Spasm of tail of un inoculated mice spread to limb and other side and the animal dies 8/23/2015 Dr.T.V.Rao MD @ Rao's Microbiology 36

Tetanus bacteria grow in RCM Medium:

Tetanus bacteria grow in RCM Medium Bacteria grown in Robertson cooked meat medium 8/23/2015 Dr.T.V.Rao MD @ Rao's Microbiology 37

Treatment:

Treatment Treatment involves debridement, the antibiotic metronidazole* active immunization  with tetanus toxoid , and passive immunization  with tetanus immune globulin. Prevention is through active immunization with tetanus toxoid**. The toxoid stimulates the body to make neutralizing antibodies against the binding component of the tetanus toxin. Once the antibody binds to the toxin, the toxin can no longer bind to the receptors on the host cell membrane 8/23/2015 Dr.T.V.Rao MD @ Rao's Microbiology 38

Prevention:

Prevention Tetanus carries a 35% mortality rate, making prevention very important! The best course is childhood immunizations, with consistent booster doses, and prompt cleaning of wounds with hydrogen peroxide. 8/23/2015 Dr.T.V.Rao MD @ Rao's Microbiology 39

Prophylaxis:

Prophylaxis Surgical attention Antibiotics Immunization Antibiotics <4 hours Erythromycin 5000 mg Bid Pencillin Local treatment with bacitracin, and neomycin 8/23/2015 Dr.T.V.Rao MD @ Rao's Microbiology 40

Passive Immunization:

Passive Immunizati on Tetanus antitoxin 1,500 IU s/c IM Test dose to be given Human Anti tetanus globulin 250 units 8/23/2015 Dr.T.V.Rao MD @ Rao's Microbiology 41

Passive Immunization:

Passive Immunization Antitoxin ( tetanus immune globulin ) should be administered immediately. This will inactivate toxins in the blood. Wounds should be debrided to remove dead tissue or foreign bodies. Antibiotics should be given to inhibit growth of C. tetani . A tetanus toxoid booster immunization should be given to patients who have not received one within the last 5 years. If spasms occur, antispasmodic drugs should be used and respiration maintained by a breathing apparatus if necessary. 8/23/2015 Dr.T.V.Rao MD @ Rao's Microbiology 42

TETANUS TOXOID:

Tetanus toxoid was developed by Descombey in 1924, Tetanus toxoid immunizations were used extensively in the armed services during World War II. Although the rates of seroconversion are about equal,the adsorbed toxoid is preferred because the antitoxin response reaches higher titers and is longer lasting than that following the fluid toxoid. TETANUS TOXOID 8/23/2015 Dr.T.V.Rao MD @ Rao's Microbiology 43

Tetanus toxoid:

Tetanus toxoid Tetanus toxoid consists of a formaldehyde-treated toxin. There are two types of toxoid available — adsorbed (aluminum salt precipitated)toxoid and fluid toxoid 8/23/2015 Dr.T.V.Rao MD @ Rao's Microbiology 44

Active Immunization:

Active Immunization 1 st dose - 6 th week 2 nd dose - 10 th week 3 rd dose - 14 th week 1 st booster - 18 th month 2 nd booster - 6 th year 3 rd booster - 10 th year 8/23/2015 Dr.T.V.Rao MD @ Rao's Microbiology 45

Passive Immunization:

Passive Immunization ATS(equine) Ig- 1500 IU/s.c after sensitivity test (or) 2. ATS(human) Ig- 250-500 IU, no anaphylactic shock, very safe and costly. 8/23/2015 Dr.T.V.Rao MD @ Rao's Microbiology 46

Treatment of Tetanus patients:

Treatment of Tetanus patients Hospitalization Tracheotomy Human TIG 10,000 IU Pencillin, Metronidazole ATS IV Give active immunization. 8/23/2015 Dr.T.V.Rao MD @ Rao's Microbiology 47

Slide48:

8/23/2015 Dr.T.V.Rao MD @ Rao's Microbiology 48

PREVENTION OF NEONATAL TETANUS:

PREVENTION OF NEONATAL TETANUS 2 doses of T.T to all pregnant women between 16 to 36 weeks of pregnancy with an interval of 1 to 2 months between the two doses. The first dose as early as possible & the second dose a month later preferably 3 weeks before delivery. If the pregnant woman is previously immunized, a booster dose is sufficient. If the pregnant woman is not immunized, then the new born should be protected against tetanus by giving tetanus human immunoglobulin 750 IU with in 6 hours of birth. 8/23/2015 Dr.T.V.Rao MD @ Rao's Microbiology 49

Triple Antigen vaccine:

Triple Antigen vaccine Triple Antigen vaccine is a combination of Diphtheria, Tetanus, and Pertussis. The vaccine stimulates the production of antibodies to immunize the body against the causative agents of the three diseases listed above 8/23/2015 Dr.T.V.Rao MD @ Rao's Microbiology 50

Epidemiology :

Epidemiology Endospores are found in most soils and in the intestinal tract of many animals and humans. Although exposure to endospores is common, disease is uncommon except in countries with poor medical care and vaccination compliance. It is estimated that there is more than one million cases a year worldwide, with a mortality rate of 20% to 50%. Most deaths occur in neonates and originates from infection of umbilical stumps in mothers that have no immunity. 8/23/2015 Dr.T.V.Rao MD @ Rao's Microbiology 51

Prevention is Better than Cure:

Prevention is Better than Cure 8/23/2015 Dr.T.V.Rao MD @ Rao's Microbiology 52

Slide53:

Program Created and Designed by Dr.T.V.Rao MD for the benefit of Universal Education on Infectious diseases Email doctortvrao@gmail.com 8/23/2015 Dr.T.V.Rao MD @ Rao's Microbiology 53

authorStream Live Help