M3 - Anaerobic bacteria Flashcards

1
Q

what are obligate anaerobes

A
  • organisms unable to grow in presence of O2

- require low reduction/oxidation potential (Eh)

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2
Q

what are facultative anaerobes

A
  • organisms grow under aerobic or anaerobic conditions

E.coli, staphylococci, streptococci

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3
Q

what are obligate aerobes

A
  • organisms unable to grow in absence of O2

pseudomonas, Nesisseria

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4
Q

what are microaerophiles

A

organisms that need small amount of O2 (less than normal atmospheric level)
(Helicobacter)

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5
Q

what are capnophiles

A

organisms that need 5-10% CO2 for growth

Brucella

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6
Q

what are the 4 ways to cultivate anaerobes

A
  1. anaerobic jars
  2. anaerobic cabinets
  3. roll-tube techniques/Hungate method
  4. robertons cooked meat (RCM) medium
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7
Q

how do anaerobic cabinets work to cultivate anaerobes

A

▹ provides complete working chamber for anaerobes
▹ contains atmos of 80%N2, 10% H2, 10 CO2
▹ pass materials in + out via air lock

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8
Q

how do anaerobic jars work to cultivate anaerobes

A

a) vacuum replacement method
- remove air with vacuum pump
- replace atmos with gas mix
- include palladium catalyst

b) gas-generating sachets
- add water, H2+CO2 form

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9
Q

what are 3 groups in gram + bacteria

A
  1. cocci
  2. spore forming rods
  3. non-sporing rods
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10
Q

what is example of cocci in gram+

A

peptostreptococcus

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11
Q

what is example of spore-forming rods in gram+ bacteria

A

clostridium

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12
Q

what are 4 examples of non-sporing rods in gram+ bacteria

A
  • propionibacterium
  • eubacterium
  • actinomyces
  • bifidobacterium
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13
Q

what are 3 groups in gram - bacteria

A
  1. cocci
  2. rods + filaments
  3. spirochaetes
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14
Q

what is example of cocci in gram-

A

veillonella

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15
Q

what are 5 examples of rods + filaments in gram+ bacteria

A
  • bacteriodes
  • fusobacterium
  • prevotella
  • campylobacter
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16
Q

what is 2 examples of cocci in gram-

A
  • spirochaetes

- treponema

17
Q

what are dentoalveolar/periapical abscesses

A

abscesses that develop around apices of teeth with necrotic + infected root canals
- oral streptococci + oral anaerobes
(obligate anaerobes predominate)

18
Q

what is osteomyelitis and caused by what

A

rare disease -> inflammation of jaw bone cavity

anaerobic gram- rods + streptococcus spp.

19
Q

what is chronic marginal gingivitis

A

inflammation confined to soft tissues of gingival as results of plaque accumlating

20
Q

what is acute ulcerative gingivitis (AUG) and what is it caused by

A

grey gingival pseudomembrane - easily removed revealing bleeding area +destruction of interdental papillae

  • spirochaetes (Treponema), prevotella + Fusobacterium
21
Q

what is periodontitis + what is it caused by

A

gingival inflammation to deep tooth structures with destruction of periodontal ligament + alveolar bone

  • porphyromonas gingivalis, aggregatibacter, prevotella intermedia
22
Q

what is pericoronitis and what is ti caused by

A

inflammation of soft tissue that surround crown of partially erupted tooth (esp lower 3rd molars)

  • oral anaerobes (P. intermedia + Fusobacterium nucleatum)
23
Q

what is peri-implantits + what is it caused by

A

inflammation around implant systems that replace missing teeth

  • oral anaerobes esp P.gingivalis + P.intermedia
24
Q

what is actinomycosis + cause by what

A

formation of chronic granuloma with swelling
chronic - discharging sinuses can be seen

  • actinomyces israelii
25
Q

what is sialadenitis + caused by what

A

infection of salivary glands

- streptococcus spp, staphylococcus + gram- anaerobes

26
Q

where can infection with non-sporing aerobes occur

A

head + neck
respiratory
GI+GU tracts
in abscesses + wound infections - can associated with bad smelling pus + discharge

27
Q

what is clostridium

A

▹ gram +pos large anaerobic rods
▹ produce endospores - allows organisms to survive in adverse conditions (soil/skin)
▹human/animal intestine + plant/animal matter

28
Q

what are 4 important species of clostridium

A
C.botulinum = (botulism)
C.perfringens = gas (gangrene/food poisoning) 
C.tetani = (tetanus)
C.difficle = (pseudomembranous colitis)
29
Q

what causes tetanus and how is it caused

A

▹ clostridium tetani
▹ after contamination of deep wound/injury
▹ spores in soil + env
▹ C.tetani preoduce tetanospasmin (neurotoxin) & tetanolysin (haemolysin)

30
Q

what happens when you get tetanus and how is it prevented

A

▹ trismus (lockjaw) dysphagia, muscle spasms
▹ death by resp/cardiac failure
▹ prevent by vaccine with tetanus toxoid (inactivated) IF UNEXPOSED
▹ IF EXPOSED = passive immunisation with HTIG (toxin antibody)

31
Q

what is botulism caused by and how

A

▹ clostridium botulinum
▹ after ingestion of pre-formed toxin in food (meats + cans)
▹ makes potent neurotoxins (types A-G)

32
Q

what types of neurotoxins cause human botulism

A

types A, B, E

33
Q

how does C.botulinum toxins affect the body

A

▹ bacteria produces extremely potent neurotoxins

▹ toxin blocks release of Ach from peripheral motor nerve endings

34
Q

what are the symptoms of botulism and how is it prevented

A

▹ vomit, thirst, muscle paralysis
▹ death by resp/cardiac failure
▹ prevent = control processed foods

35
Q

what is gas gangrene caused by

A

▹ polymicrobial infection of wounds

▹ histotoxic clostridia -> produce range of lethal + necrotising toxins

36
Q

what species of clostridia can cause gas ganrene

A

C.perfringens
C.novyi
C.septicum

37
Q

what are the 3 stages of infection during gas gangrene

A

contamination
clostridial cellulitis
myonecrosis (gas gangrene)

38
Q

what are the symptoms of gas gangrene and how is it prevented

A

▹ gas forms in tissue
▹ fever, shock, coma death
▹ treatment can mean amputation
▹ prevented = proper wound management