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Anaerobic Bacteria part II

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Drainage and debridement are used to expose tissues to aerobic condition. ... Chest pain, fever, wgt loss and hemoptysis. Gram postive spore-forming rods ... – PowerPoint PPT presentation

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Title: Anaerobic Bacteria part II


1
Anaerobic Bacteriapart II
  • Praphan Luangsook

2
Conclusion
  • Terms anaerobe, facultative anaerobe, obligate
    anaerobe etc
  • Toxic of oxygen and defense mechanism from
    bacteria

3
  • Some anaerobes produce Superoxide Dismutase
  • Levels correlate with O2 Sensitivity
  • Allow survival outside of usual niche ? Cause
    Disease

4
  • Redox potential
  • Anaerobes as Normal flora
  • Anaerobic infection
  • Characteristic mechanism
  • Clues
  • Specimen collection
  • Culture and identification

5
Classification
  • - Anaerobic GPC- Anaerobic GNB
  • - Anaerobic GPB, non-sporeforming- Anaerobic
    GPB, sporeforming

6
Sporeforming, gram positive bacilli
  • Genus Clostridium
  • all species form endospores
  • most Clostridium hemolysis RBC
  • active form secrete exotoxins as
    tetanus, botulism and gas gangrene

7
Clostridium perfringens
  • produces a huge array of invasins and exotoxins
  • causes wound and surgical infections that lead to
    gas gangrene
  • Protease and toxin activity are apparent in
    wound.
  • Alpha-toxin (phospholipase C or lecithinase)
  • Theta toxin hemolytic and necrotizing effects
  • Spreading factors DNAse, collagenase and
    hyaluronidase

8
  • C. perfringens also produces an enterotoxin and
    is an important cause of food poisoning.

9
  • Double zone hemolysis
  • lecithinase , motile -
  • C.perfringens A-E
  • Food poisoning type A
  • enteritis necroticans type C beta-toxin to
    damage intestinal villi
  • gas gangrene

10
Treatment
  • Treatment Pen G, tetracycline, antitoxin
  • Passive anti-alpha toxin theraphy
  • Hyperbaric oxygen is another form of wound
    treatment.
  • Drainage and debridement are used to expose
    tissues to aerobic condition.

11
Clostridium perfringens
B
  • A

A. Double zone hemolysis on BRU/BA B. Gram
positive bacilli, car-box shaped
12
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13
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14
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15
??????????? C. perfringens
Common
Rare
  • Enterotoxin producing type A
    beta-toxin producing type C

?????????????????????????????????????????????????
?????????????????????????
???????????, ????????????
???????????????
???????????
???????????, ?????????? trypsin
16
????? enterotoxin ???????????
????? beta-toxin ???????????
- ????????????????????? - ???????????????????? -
?????????????
Acute necrotinizing
Disease (pig-bel) - ??????? - ????????????? -
???????? 50
????????
17
Clostridium tetani
  • the causative agent of tetanus.
  • organism is found in soil and in the intestinal
    tracts and feces of various animals.
  • produces terminal spores giving it a distinctive
    drumstick appearance.
  • a typical Gram-positive cell wall, it may stain
    Gram-negative or Gram-variable, especially in
    older cells.
  • tetanus toxin or tetanospasmin

18
A
B
  • A Stained pus from a mixed anaerobic infection.
  • B Electron micrograph of Clostridium tetani
    cells.

19
Pathogenesis
  • The toxin is produced during cell growth,
    sporulation and lysis.
  • sites of action central nervous system.
  • spasms and rigidity of the voluntary muscles.
  • "lockjaw" involves spasms
  • of the masseter muscle.

20
Pathogenesis of tetanus caused by C. tetani
21
Toxin action
  • Tetanospasmin heat labile toxin,150kDa, AB type
    toxin, A bind tissue, B toxic effect
  • initially binds to peripheral nerve terminals.
  • transported within the axon and across synaptic
    junctions until it reaches the CNS
  • becomes rapidly fixed to gangliosides at the
    presynaptic inhibitory motor nerve endings, and
    is taken up into the axon by endocytosis.

22
Toxin action (cont.)
  • block the release of inhibitory neurotransmitters
    glycine and gamma-amino butyric acid (GABA)
  • If nervous impulses cannot be checked by normal
    inhibitory mechanisms, it produces the
    generalized muscular spasms characteristic of
    tetanus.

23
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24
Immunity
  • usually does not confer immunity, since even a
    lethal dose of tetanospasmin is insufficient to
    provoke an immune response.
  • Prophylactic immunization is accomplished with
    tetanus toxoid, as part of the DPT vaccine or the
    DT (Td) vaccine.

25
Treatment
  • Penicillin
  • Remove necrotic tissue
  • Muscle relaxants, sedation and assisted
    ventilation are supportive therapy

26
Clostridium botulinum
  • forms subterminal endospores.
  • widely distributed in soil, sediments of lakes
    and ponds, and decaying vegetation
  • The botulinum toxins are designated A, B, C1, D,
    E, F, and G.
  • Botulism is not spread from one person to
    another.

27
Three categories of Botulism
  • 1. Classical food-borne Botulism
  • 2. Wound botulism
  • 3. Infant botulism

28
Food-borne botulism
  • Home canned foods with low acid content
  • symptoms occur 18-36 hr nausea, vomiting, double
    vision, paralysis, respiratory failure and death
    (rate 75 for type A)
  • neurotoxin binds to nerve synapse and blocks
    release acetylcholine

29
Wound botulism
  • This type of botulism is caused by a botulism
    toxin that is produced from a wound that was
    contaminated with Clostridium botulinum.

30
Infant botulism
  • This type of botulism occurs when infants consume
    spores of Clostridium botulinum, which then
    release toxins in the intestines.
  • Most common, associated with honey, floppy baby,
    Sudden infants death syndrome (SIDS)

31
Pathogenesis of botulism caused by C. botulinum
32
How does botulinum toxin work?
- Normally, muscle contraction is stimulated by
a chemical called acetylcholine. - In some
diseases, such as cerebral palsy, too much
acetylcholine is released, overstimulating the
muscle and resulting in muscle spasm. - Botulinum
toxin releases muscle contraction by inhibiting
acetylcholine release.
33
Normally when a message comes from the nerve, Ach
is released and the muscle contracts
When botulinum toxin is added, the release of Ach
is reduced and the muscle stays relaxed.
34
How botox works?
35
Botox Cosmatic/medical application
Toxin A
Before
After
36
Diagnosis
  • Spinal Tap (Also called a lumbar puncture)
  • A small amount of cerebral spinal fluid
    (CSF) can be removed and sent for testing to
    determine if there is an infection or other
    problems.
  • Test for botulism toxin in the patients serum or
    stool

37
Prevention
  • proper food handling and preparation.
  • spores survive boiling (100 OC at 1 atm) for
    more than one hour.
  • Because the toxin is heat-labile boiling or
    intense heating (cooking) of contaminated food
    will inactivate the toxin.
  • Antitoxin effective against toxin types A-E

38
Treatment
  • No antibiotic give except in infant botulism
  • Potent trivalent (A,B,E) antitoxin

39
Clostridium difficile
  • Major cause of antibiotic-associated diarrhea and
    pseudomembranous colitis
  • motile , gelatin , casein
  • C.difficile toxin A, B (heat and acid labile)
  • toxin A enterotoxin
  • toxin B cytotoxin cell damage

40
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41
Pathogenisis of pseudomembranous colitis cause by
C. defficile
42
  • leukocytosis in feces 30,000-50,000 cells/ml
  • Prior symptoms acute diarrhea, electrolyte loss,
    nausea, sepsis, shock and death
  • Nosocomial infection
  • Treatment vancomycin

43
Non-sporeforming, gram negative bacilli
  • normal flora in GI tract of human and animal
  • Bacteroides fragilis group, Fusobacterium,
    Porphyromonas, Prevotella, and etc.
  • some species of Prevotella and Porphyromonas
    produce a dark pigment

44
A B
A. Bacteroides fragilis B. Fusobacterium nucleatum
45
Bacteroides fragilis group
  • Gram negative, pleomorphic bacilli
  • Resistance to PenG, Cephalosporin, tetracycline
  • produce beta-lactamase
  • bile-tolerant

46
Pathogenicity
  • Adherence ??????????? agglutinate ??? RBC
    ??????????? fimbriae-like
  • Capsule acidic polysaccharides, ??????????
    phagocytosis ??? WBC
  • Enzymes collaginase, protease, hyaluronidase,
    fibrinolysin, Dnase,, etc.
  • Endotoxins (LPS) activate C3 pathway,
    ??????????????????? PMNs ????

47
  • Beta-lactamase production
  • B. fragilis protect themselves and other
    species in mixed infections
  • Superoxide dismutase production
  • Protects bacteria from toxic O2 radicals as they
    move out of usual niche

48
Fusobacterium
  • Delicate gram (-) rods
  • Tapering ends
  • F. nucleatum
  • Mouth, Upper Resp. tract, GI tract, Genital tract
  • Head, neck and lower respiratory tract infections
  • F. necrophorum
  • Anaerobic tonsillitis/pharyngitis
  • Involve jugular vein ? Sepsis
  • Liemeres Disease

49
Prevotella Porphyromonas
  • Small, pale staining coccobacillary gram (-) rods
  • Dental plaque and gingival crevices
  • Infections of oral cavity and upper respiratory
    tract

50
Anaerobic gram positive cocci
  • Family Peptococcaceae
  • Rearrangement single, pairs, chains
  • motile - , flagella - , endospore -
  • colonies size from 0.5-2 mm in diameter
  • Susceptible PenG, Clindamycin,
  • Chloramphenicol, Cephalosporin

51
  • Normal flora in mouth, URT, large intestine, GU
    and skin
  • Sensitive to Sodium polyanethol sulfonate (SPS, gt
    12 mm) Peptostreptococcus anaerobius
  • indole in P. asaccharolyticus

-

52
Non-sporeforming, gram positive bacilli
  • Actinomyces, Propionibacterium
  • Actinomyces found sulphur granule in pus,
    Actinomycosis
  • P.acnes resident flora at skin, sometimes
  • contaminated in blood
  • culture, endocarditis
  • ? acne

53
Anaerobic Gram Positive Non-sporeforming Bacilli
  • Bifidobacterium
  • Lactobacillus
  • Nl flora of gut and vagina
  • Ferments glucose to lactic acid (vaginal pH lt5)
  • Mobiluncus
  • Eubacterium

54
ACTINOMYCES
  • Anaerobic, filamentous, gram positive bacillus
  • Exhibit true branching
  • Mykes Greek for fungus
  • Thought by early microbiologist to be fungi
    because of
  • Morphology
  • Disease they cause

55
ACTINOMYCOSIS
  • Not highly virulent (Opportunist)
  • Component of Oral Flora
  • Periodontal pockets
  • Dental plaque
  • Tonsilar crypts
  • Take advantage of injury to penetrate mucosal
    barriers
  • Coincident infection
  • Trauma
  • Surgery

56
ACTINOMYCOSIS
  • Form indurated masses with fibrous walls and
    central loculations with pus
  • Pus contains "Sulfur Granules"
  • Gritty, yellow white
  • Average diameter - 2mm
  • Composed of mineralized mycelial mass
  •  
  • Chronic infection
  • Form burrowing sinus tracts to skin or mucus
    membranes
  • Discharge purulent material

57
Actinomycosis - sulfur granule
58
Pulmonary Actinomycosis
  • 15 of cases
  • Aspiration of organism from the oropaharynx
  • Slowly progressive process involving lung and
    pleura
  • May be mistaken for malignancy
  • Chest pain, fever, wgt loss and hemoptysis

59
  • Gram postive spore-forming rods
  • Clostridium - obligate anaerobes normally
    exogenous however C. difficile andC. perfringins
    may be found in the bowel flora
  • C. botulinum-produces neurotoxin which acts on
    pre-synaptic cholinergics
  • C. tetani - neurotoxin that inhibits glycine (an
    inhibitor itself). Also produces the hemolysin
    tetanolysin.

60
  • C. perfringins-toxin phospholipase C (or
    lecithinase) egg yolk medium isthe assay for
    lecithinase or lipase activity
  • C. difficile - cytotoxin is responsible for
    ulcerative colitis

61
  • Gram negative rods
  • Bacteriodes fragilis - known for its
    polysaccharide capsule which is anti-phagocytic
  • B. melaninogenicus - utilizes hemin in
    blood-containing media and deposits a black
    pigment (which is not melanin). It is most
    frequently found in the oral cavity and works
    synergistically in fusospirochetal disease and
    advanced peridontitis produces enzymes and
    chronic inflammation.
  • Fusobacterium necrophorum- distinguished from
    Bacteroides on the basis of end products - also
    produces enzymes that allow it to be invasive.

62
  • Gram positive cocciPeptostreptococcus -
    frequently involved in respiratory infections

63
  • Gram positive non-spore-forming rods-- not
    necessarily obligate anaerobes, but may be
    capnophilic (utilizing carbon monoxide)Actinomyce
    tes - produces the actinomycoses, involved in
    chronic infections, particularly localized
    respiratory infections

64
  • Gram negative cocciVeillonella (not usually
    pathogenic)
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