07-05-2014, 10:46 AM
TERM PAPER OF ADVANCED MICROBIOLOGY
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CLOSTRIDIUM TETANI
CLASSIFICATION :-
Division-Prokaryotes
Kingdom - Bacteria
Phylum - Firmicutes
Class - Clostridia
Order - Clostridiales
Family - Clostridiaceae
Genus - Clostridium
Species - Clostridium tetani
INTRODUCTION:-
Clostridium tetani was discovered in 1884 by a German physician Arthur Nicolaier. He found that C.tetani causes tetanus when he injecting test animals with garden soil which contain bacteria. Clostridium tetani is an anaerobic bacterium that is found in soil and animal intestinal tracts. C. tetani bacteria are single-celled and do not contain any membrane-bound organelles, such as a nucleus. It is a Gram-positive bacteria as it lacks an outer lipopolysaccharide membrane and possesses only a thick peptidoglycan cell wall.C.tetani is a rod-shaped bacteria and have flagella in vegetative form and drumstick in shape in its spore form. Eleven strains of C.tetani are identified and all of these strains produce an neurotoxin known as tetanospasmin. This toxin is responsible for Tetanus.[1]
As Clostridium tetani bacteria are anaerobic so they derieve nutrition by the process of fermentation. Acetic acid, butyric acid, butanol and acetone are byproducts of the bacterial fermentation. Certain strains of C. tetani produce different enzymes that are used to externally digest organic material in preparation for fermentation. In the anaerobic condition C. tetani is primarily found in soil, manure, and intestinal tracts. [2]
METHODOLOGY:-
The infection begins when endospores of C. tetani enter an anaerobic wound. Tetanus can also occur in burn victim, in patients receiving intramuscular injections, person obtaining a tattoo, in persons with frostbite, dental infections, penetrating eye injuries and umbilical stump infections. Other risk factors include diabetes, chronic wounds(skin ulcers.gangrene) parental drug abuse and recent surgery .Unvaccinated mother, home delivery, and unhygienic cutting of the umbilical cord increase susceptibility to tetanus. History of neonatal tetanus in a previous child is a risk factor for subsequent neonatal tetanus. Potentially infectious substances applied to the umbilical stump (e.g., animal dung, mud, clarified butter) are risk factors for neonates. Immunity from tetanus decreases with advancing age. Since the bacterium is an obligate anaerobe, an anaerobic environment is needed for the endospores to germinate and the vegetative bacteria to grow. Vegetative bacteria eventually produce tetanospasmin which is responsible for symptoms of tetanus. The tetanus toxin initially binds to peripheral nerve terminals.
DIAGNOSIS: -
The symptoms of tetanus are quite distinctive and a doctor can diagnose the disease simply by observing the patient. Painless spasm of the muscles of the jaw, difficulty in opening the mouth, contraction of the muscles on the forehead and mouth are the characteristic symptoms. Knowing whether or not the patient has had a tetanus vaccination also helps a doctor make their diagnosis. Other signs of being generally irritable, muscle spasms, and poor ability to take in liquids (poor sucking response), Irregular heartbeat, changes in blood pressure
TREATMENT:-
When a tetanus infection becomes established, treatment usually focuses on controlling muscle spasms stopping toxin production, and neutralizing the effects of the toxin. Treatment includes administration of tetanus immune globulin (TIG) which comprises antibodies which inhibit tetanus toxin (also known as tetanus antitoxins) by binding to and removing unbound tetanus toxin from the body. Binding of the toxin to the nerve endings is an irreversible event, and TIG is ineffective at removing bound toxin. Recovery of affected nerves requires the sprouting of a new axon terminal. Large doses of antibiotic drugs (such as metronidazole or intramuscular penicillin G) are also given once tetanus infection is suspected, to halt toxin production. The wound must be cleaned. Dead and infected tissue should be removed by surgical debridement. Metronidazole treatment decreases the number of bacteria but has no effect on the bacterial toxin. Penicillin was once used to treat tetanus, but this treatment is no longer used, owing to a theoretical risk of increased spasms. However, its use is recommended if metronidazole is not available. Passive immunization with human anti-tetanospasmin immunoglobulin or tetanus immune globulin is crucial. If specific anti-tetanospasmin immunoglobulin is not available, then normal human immunoglobulin may be given instead. All tetanus victims should be vaccinated against the disease or offered a booster shot.
PREVENTION:
There are two important ways to prevent tetanus: getting vaccinated against tetanus along with other routine immunizations, or, after an injury that could cause tetanus, receiving a shot (post-exposure tetanus prophylaxis).For kids, tetanus immunization is part of the DTaP (diphtheria, tetanus, and a cellular pertussis) vaccinations. They typically receive a series of four doses of DTaP vaccine before 2 years of age, followed by a booster dose at 4 to 6 years of age. After that, a booster (Tdap) is recommended at 11 to 12 years of age, and then a tetanus and diphtheria booster every 10 years through adulthood. Post-exposure tetanus prophylaxis also involves getting tetanus shots, but after an injury occurs. Shots given will depend on the number of years since the patient's last booster, the total number of tetanus vaccinations the patient has received, and the nature of the wound. The doctor may recommend a tetanus booster Td, DTaP, or Tdap, depending on the patient's age and previous immunizations and an injection of tetanus immune globulin (TIG) to neutralize any toxin released by the bacteria. Neonatal tetanus can be prevented by making sure that all pregnant women have had their tetanus immunizations, by delivering babies in sanitary conditions, and by proper umbilical cord care. If you are pregnant, discuss your immunization record with your obstetrician well before your due date. Any skin wound — especially a deep puncture or a wound that may be contaminated with feces, soil, or saliva — should be cleaned and dressed right away. Although it's important to clean all wounds, remember that cleaning is not a substitute for immunization [8].
RESULTS AND DISCUSSION:
Tetanus remains a severe disease occurring primarily among persons who are unvaccinated or inadequately vaccinated. Adults aged greater than or equal to 60 years continue to be at highest risk for tetanus and for severe disease. However, the overall incidence of tetanus has decreased slightly since the late 1980s and early 1990s. Older adults are at highest risk for tetanus because of the low prevalence of immunity to tetanus. Tetanus remains a clinical diagnosis because confirmatory laboratory tests are not available for routine use. Isolation of the organism from wounds is neither sensitive nor specific: anaerobic cultures of tissues or aspirates usually are not positive, and the organism might be grown from wounds in the absence of clinical signs and symptoms of disease. Tetanus is preventable through both routine vaccination and appropriate wound management. Vaccination with a primary series of three doses of TT-containing vaccine and booster doses of Td every 10 years are highly effective in preventing tetanus.
CONCLUSION:-
Tetanus (commonly called lockjaw) is a disease manifested by uncontrolled muscle spasms. Tetanus is caused by the toxin (poison) produced by the bacteria, Clostridium tetani. This disease is frequently fatal, especially to the very old or very young. Tetanus is preventable by immunization or through administration of tetanus immune globulin.It occurs predominantly in developing countries among newborn infants, children, and young adults, especially in unimmunized or inadequately immunized adults over 50 years of age. The symptoms are often jaw or neck stiffness, difficulty swallowing, and irritability. There may be pain or tingling at the site of inoculation (where the tetanus bacteria entered), followed by spasticity of nearby muscles. The diagnosis is made clinically by the medical history and physical findings. Immune globulin, given intramuscularly, is the immediate treatment of unimmunized individuals exposed to material likely to contain the tetanus bacteria. Treatment includes bed rest and quiet conditions.Antimicrobial drugs, such as penicillin, are used to eradicate the bacteria. Tetanus is completely preventable by active immunization.