Actinomycetes- Anaerobes.

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Actinomycetes- Anaerobes.
2010-11-07 12:41:42

VPTH 605 Exam 2
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  1. Actinomycetes
    Gram Pos rods and branching filaments, chronic purulent and granulomatous infections; hard to treat with Abx
  2. Arcanobacterium pyogenes
    AKA Actinomyces pyogenes, Corynebacterium pyogenes
  3. Actinomyces pyogenes
    mucosal flora of swine, facultative anaerobe; chronic purulent infections- mastitis, endometritis, endocarditis,etc; opporunistic, polymicrobial infections
  4. Actinomyces pyogenes Tx
    Drainage, penicillin
  5. Actinobacilum suis (AKA Actinomyces suis)
    Anaerobe, necrotic purulent pyelonephritis & cystitis in swine
  6. Actinomyces viscosus
    oral flora of dogs,humans; factultative anaerobe
  7. Actinomycosis in dogs and cats
    Actinomyces viscosus- chronic pyogranulomatous infections under skin or in body cavities (pyothorax); Tx- drainage, pencillin
  8. Actinomyces bovis
    Oral flora of cattle, strict anaerobe, sulfur granules on microscopy (see club formation of proteins and CaPO4)
  9. "Lumpy Jaw" of Cattle
    Actinomyces bovis; traumatic lesions in the oral cavity leading to chronic granulomas involving bones (NOT actinobacillosis); fistulation through the skin or oral mucosa
  10. Actinomyces bovis Tx
    Drainage, Iodine solutions, penicillin
  11. Nocardia aseroides
    Ubiquitous in soil, Strict Aerobe, produces mycolic acid, Facultative intracellular pathogen (cell mediated immunity Imp't)
  12. Nocardia aseroides causes:
    chronic, granulomatous fistulous infections in the oral cavity, the subcutis and internal organs (lungs - aspiration pneumonia); mastitis (iatrogenic)
  13. Nocardia aseroides virulence properties
    bind to and invade endothelial cells (can invade midbrain); mycolic acid- toxic, inhibits killing by macrophages and neutrophils; immunostimulant
  14. Nocardia aseroides Lab Dx
    long branching filaments, weakly gram +, +/- acid-fast
  15. Nocardia aseroides Tx
    Drainage, Sulfonamide-trimethoprim (pencillin resistant)
  16. Dermatophilus congolensis
    obligate parasite of animals, Strict aerobe, parallel filaments (divides in both directions); release of zoospores; germ tube formation
  17. Dermatophilus congolensis Dz
    Streptothricosis (dermatophilosis) in ruminants, horses (dogs, cats, humans) - exudative dermatitis (“ rain rot” or “rain scald” in horses; "lumpy wool", "strawberry foot rot" in sheep)
  18. Dermatophilus congolensis Virulence factors
    extracellular proteases (keratinase)
  19. Dermatophilus congolensis Tx
    Hygiene, Iodine, Penicillin + Streptomycin
  20. Nonspore-forming Anaerobes
    Oral and gut flora and humans; infections require simultaneous trauma of deep tissus, ischemia, decr. O2 tension, and contamination (fecal, bites); Polymicrobial infections with facultative anaerobic bacteria, synergistic process (maintenance of a low redox potential); causes gingivitis, abscesses, perotinitis, tissue necrosis
  21. Nonspore-forming Anaerobe Lab Dx
    Sealed Syringe (Bx > Swab); if use swab, used anaerobic transport media
  22. Nonspore-forming Anaerobes Tx
    Sx (drainage), Abx (resistant to aminoglycosides, fluoroquinolones)
  23. Fusobacterium necrophorum
    Gram neg with beaded filaments (gram stain); found with mixed infections (A. pyogenes, bacteroides spp,etc.); found in necrobacillosis, phlegmonous and ulcerative stomatitis in cattle and swine; rumenitis; liver abcess; Pericarditis (foreign body); Footrot in cattle (Interdigital phlegmonous infections); Thrush in horses
  24. Fusobacterium necrophorum Tx
    Penicillin- susc., no Vx, Good Hygiene (survive for months in humid bedding or soil)
  25. Prevotella, porphyromonas, bacteroides
    Gram neg anaerobes mixed w/ other anaerobes; cause oral infections, aspiration pneumonia, pyothorax, castration wounds, umbilical infections, sepsis
  26. Dichelobacter (Bacteroides) nodosus
    Obligate of hooves ruminants (short life in soil); causes contagious footrot in sheep
  27. Dichelobacter nodosus frequently mixed with
    A. pyogenes, F. necrophorum, etc.
  28. Dichelobacter nodosus Virulence Factors
    have heat-stable protease (keratinase); fimbriae impart antigenic variability
  29. Dichelobacter nodosus Tx
    Penicillin- susc.; hygiene- hoof trimming, disinfectant baths
  30. Capnocytophaga canimorsus
    commensal in oral cavity of cats and dogs; complicates bite wounds (sepsis); obligate anaerobe
  31. Capnocytophaga canimorsus virulence factors
    LPS, sialidase removes acids on host surface; blocks macrophage killing
  32. Spore-forming anaerobes
    Gram +, cause abscesses, mastitis in cows; mixed with other infections
  33. Clostridia (spore-forming anaerobes)
    Lg, Gram + rods; spores only killed by 121 deg. C for 20 min; widely distributed saprophytes- soil, intestine; some produce serious exotoxins
  34. Clostridium tetani
    widespread- intestine of animals and humans, soil
  35. Tetanus
    Clostridium tetani in humans and horses (most susceptible; typically occurs after wound infections; environment with anaerobic conditions prompts spore germination and exotoxin production
  36. Clostridium tetani produces
    Neurotoxin (tetanospasmin)- a highly toxic protein that binds to peripheral nerves near wound (irreversible binding to gangliosides of nerve cells),Transmitted to cranial nerve nuclei; has protease activity on specific vesicle-associated membrane proteins; Blocks release of inhibitory transmitters (e.g.GABA); Spastic paralysis (protrusion of the nictitating membrane, sawhorse stance; in humans, "sardonic smile", lockjaw - trismus); death by respiratory failure
  37. Tetanus Tx and prevention
    Toxoid Vx; sedation; sx debridement, penicillin; antitoxin (frequently too late)
  38. Clostridium Botulinum
    Habitat- soil and marine sediment; food contamination by spores; cattle, horses, and birds are highly susceptible (Not carnivores and swine); suspicious food- 100 deg. C for 10 min inactivates toxin
  39. Botulism
    by C. botulinum; Intoxication by exotoxins previously produced in food, after germination of spores under anaerobic conditions, e.g. spoiled silage, rotting vegetables or carcasses, contaminated cans; wound botulism; infant botulism "shaker foal syndrome"
  40. C. botulinum produces
    Neurotoxins (8 serotypes)- Most potent known toxins; Heat-labile proteins, resistant to enteric proteases; Bind to gangliosides at motor-neuromuscular junctions; Protease activity on specific vesicle-associated membrane proteins; Block the release of the neurotransmitter acetyl-choline, inhibition at peripheral cholinergic synapses; Death by resp. failure (flaccid paralysis)
  41. C. botulinum Tx and Prevention
    Toxoid Vx for cattle (need specific serotype); ASAP tracheotomy and antitoxin
  42. Histotoxic Clostridia
    C. Novyi, haemolyticum, chauvoei, perfringens, septicum
  43. Clostridium Perfringens
    have at least 2 major lethal toxins; produces Gas gangrene (type A); affects ruminants, horses, humans (wartime-civilwar); needs anaerobic conditions; 2 hemolysins responsible for leukostasis, vasc. dysfunction, and capillary leak -> necrosis, and gas formation in muscles (gangrene), and toxemia; often mixed infection with other Clostridia
  44. C. Perfringens Tx
    Sx and Abx, Vx (toxoid specific)
  45. C. Perfringens also causes
    Enterotoxemia by: Type C - b toxin (protease sensitive), necrotizing hemorrhagic enteritis in neonatal farm animalsType D - e toxin (prototoxin, activated by enteric proteases - necrosis, lethal, plasmid-encoded), "Pulpy kidney" disease of sheep and goats (sudden change to a rich diet); brain edema
  46. Clostridium chauvoei
    Blackleg in ruminants; entry through gut or wounds (bacteremia); germination and multiplication in traumatized muscle; typical lesions (bubbles, rancid odor) rarely found; Vx prevents this
  47. Clostridium chauvoei Produces
  48. Clostridium Septicum
    Malignant edema- ruminants, horses, pigs (due to exotoxins similar to C. chauvoei); entry through wounds
  49. C. novyi
    various types produce different toxins (and cause different dz); Gas Gangrene (type A)- sheep, cattle, human;
  50. Infectious necrotic hepatitis (type B)
    C. Novyi; "Black Dz"- sheep, cattle, horse); Liver fluke infections cause anaerobic conditions for the germination of spores in the liver -Exotoxins (4)
  51. C. novyi Tx and control
    Elimination of the snail (flukes); vaccines
  52. Clostridium haemolyticum
    Causes Bacillar hemoglobinuria ("red water")- cattle and sheep; pathogenesis similar to "Black Dz" from flukes; produces exotoxins cause intravascular hemolysis
  53. Clostridium difficile
    causes Pseudomembranous colitis- humans, horses, dogs; Assoc. with previous Abx treatment which suppresses normal anaerobic flora; unharmed spores germinate; Toxins A and B