Micro 23

  1. Tetanus
    • Lockjaw
    • 1. Clostridium tetani spores form dust or dirt enter wound
    • 2. In anaerobic wounds, spores germinate and vegetative bacteria release an exotoxin called tetanospasmin
    • 3. Tetanospasmin is carried to central nervous system by motor nerve axons or by bloodstream
    • 4. Toxin prevents any inhibitory neurons it reaches from functioning
    • 5. Corresponding neurons, which cause muscles to contract, act unopposed by inhibitory neurons
    • 6. Result is sustained, painful cramp like muslce spasm
  2. Tetanus:
    Causative agent
    S/S: restlessness, irritability, difficulty swallowing; muscle pain and spasm in jaw, abdomen, back or entire body

    Cause: Clostridium tetani
  3. Tetanus:
    • Tetanus results from tetanospasmin, an exotoxin produced by bacterium
    • Toxin is carried to brain and spinal cord by motor nerve axons or circulating blood
    • Toxin acts against nerve cells that normally inhibit muscle contraction
    • Other nerves that normally cause muscle contraction then act unopposed, causing muscle spasms
  4. Tetanus:
    • Organisms common in soil
    • Spores contaminate wounds, germinate in those having anaerobic conditions, particularly dirty or puncture wounds
  5. Tetanus:
    Tx and prevention
    • Lock jaw
    • Treated with metronidazole, tetanus antitoxin
    • Immunization of kids

    Prevent with tetanus immune globulin and wound cleaning
  6. Clostridial Myonecrosis
    • Gas Gangrene
    • 1. Clostridium perfringens spores enter wound with two essential characteristics: dead tissue and anaerobic conditions
    • 2. Spores germinate and the vegetative bacteria multiply in dead tissue, producing alpha-toxin
    • 3. Alpha-toxin diffuses into normal tissue and kills it. Infection spreads into dead tissue, bacteria using amino acids and growth factors released from tissue by bacterial enzymes
    • 4. Swelling and gas produced by fermenting amino acids and muscle glycogen aid rapid progress of infection
    • 5. Massive amounts of alpha-toxin are produced and diffuse into bloodstream, destroying blood cells and other cells throughout body
  7. Clostridial Myonecrosis:
    • Gas Gangrene
    • S/S: Severe pain; gas and fluid seep from wound, blackening overlying skin. Shock and death commonly follow

    Cause: Clostridium perfringens
  8. Clostridial Myonecrosis:
    • Organism grows in dead and poorly oxygenated tissue and releases alpha-toxin
    • Toxin kills leukocytes and normal tissue cells by degrading lecithin in their cell membranes
    • Involvement on muscle causes chock by unknown mech.
  9. Clostridial Myonecrosis
    • Wounds of war
    • Dirt contamination of wounds, tissue death, impaired circulation to tissue as in people with diabetes or arteriosclerosis
    • Self-induced abortions
  10. Clostridial Myonecrosis:
    Tx and prevention
    • Treated by surgical removal of dirt and dead tissues of primary importance
    • Hyperbaric oxygen of possible value
    • Antibiotics to kill Veg. of marginal value

    Prevented by prompt cleaning and debridement of wounds; no vaccine
  11. Actinomycosis:
    • "Lumpy Jaw"
    • S/S: chronic disease, recurrent
    • Sometimes painful swellings open and drain pus, heal with scarring
    • Usually involves face and neck
    • Chest, abd, and pelvis are other common sites

    Cause: Actinomyces israilii

    Incubation is usually months
  12. Actinomycosis:
    • Usually begins in mouth wound, extends to face, neck or upper chest
    • Sometimes beings in lung, intestine or female pelvis
    • Always accompanied by normal microbiota
    • In tissue, grows as dense yellowish colonies called sulfur ganules
  13. Actinomycosis:
    • No person to person spread
    • A. israelii commonly part of normal mouth, upper respiratory, intestine, and vagina micro
    • Dental procedures, intestinal surgery, insertion of IUD's can initiate infections
  14. Actinomycosis: Tx and prevention
    • Because of slow growth, A. israelii infections require prolonged tx
    • Number of antibacterial meds are effective
    • No proven preventive measures
  15. Human bite wound infections:
    S/S: rapid onset, pain, massive swelling, drainage of foul-smelling pus

    Incub: usually 6 to 24 hrs

    Cause: human mouth has many microbes
  16. Human bite wound infections:
    Patho: Various mouth bacteria act synergistically to destroy tissue

    Epi: Alcohol-related violence, forcible restraint, poor mouth care and extensive dental disease
  17. Treatment for human bite wound infections
    • Usually surgical
    • No proven prevention except to avoid fights
    • Prompt cleaning and application of antiseptic is advised
  18. Pasteurella multocida bite wound infections:
    • Caused by animal bite
    • S/S spreading redness, tenderness, swelling, discharge of pus

    Incub: 24 hrs or less

    Cause: Pasteurella multocida, 
  19. Pasteurella multocida bite wound infections:
    • Introduced by bite
    • P. multocida attaches to tissue, resisting phagocytes because of it's capsule
    • Probable cell-destroying toxin
    • Extensive swelling, abscess formation
    • Opsonins develop, allowing phagocytic killing, limit spread
  20. Pasteurella multocida bite wound infections:
    Tx and prevention
    Epi: Carried by many animals in their mouth or upper respi

    • Tx: Penicillin, or other antibacterials, effective if given promptly
    • No vaccines to use in humans
    • Prompt wound care is preventive
  21. Bartonellosis:
    • Cat scratch disease
    • S/S: Pimple appears at bite or scratch, followed by local lymph node enlargemtn
    • Nodes may soften and drain pus
    • Prolonged fever and convulsions indicate spread to other body parts

    Cause: Bartonella henselae
  22. Bartonellosis:
    • Cat scratch disease
    • Bacteria enter with cat bite or scratch and reach lymph nodes, where disease usually is stopped
    • May spread to bloodstream, cause infections of heart, brain or other organs
  23. Bartonellosis:
    • Cat scratch disease
    • A zoonosis, spread amount cats by fleas, which are biological vectors and have B. henselae in the feces
    • Infected cats usually asymptomatic, but often bacteremic
    • Humans are accidental hosts
    • No person to person
  24. Bartonellosis:
    Tx and prevention
    • Promptly wash skin breaks, apply antiseptic
    • Most infections respond to antibacterial tx
    • Avoiding rough play with cats
    • Flea control in cats
  25. Streptobacillary Rat Bite Fever:
    • S/S: Chills, fever, muscle aches, HA, vomit
    • Later, rash and pain in one or more joints

    Cause: Streptobacillus moniliformis
  26. Streptobacillary Rat Bite Fever:
    • Bite wound heals without tx
    • S. moniliformis quickly invades bloodstream
    • Fevers come and go irregularly
    • Most victims recover w/o tx
    • Others, infection established in various body organs, results in death if tx not given
  27. Streptobacillary Rat Bite Fever:
    • Wild and lab rate can carry
    • Bites of other rodents and animals that prey on them can transmit disease to humans
    • Food Or drink contaminated with rodent feces can also transmit infection
  28. Streptobacillary Rat Bite Fever:
    Tx and prevention
    • Effectively tx with penicillin, other antibacterial meds
    • Control wild rats and mice
    • care in handling lab animals
  29. Sporotrichosis:
    • Rose Gardeners Disease
    • S/S: Painless, ulcerating nodules appearing in sequence in a linear pattern

    Cause: Sporothrix schenckii, a fungus
  30. Sporotrichosis:
    • Spores multiply at site of introduction by thorn, splinter, or other plant material, causing small nodule that ulcerates
    • Spores carried by lymph flow repeat the process along lymphatic vessel
    • May spread beneath skin irrespective of lymphatic vessels
  31. Sporotrichosis:
    • Rose Gardeners Disease:
    • Distributed worldwide in tropical and temperate climates
    • Occupation requiring contact with sharp plant materials at particular risk
  32. Sporotrichosis:
    Tx and prevention
    • Rose Gardeners Disease:
    • Most cases effectively treated with potassium iodide
    • Generalized infections require amphotericin B or itraconazole

    Wear protective gloves and clothing
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Micro 23