Bacteria - Structure and Classification Flashcards

1
Q

What is gram staining?

A

Method of staining bacterial cells where bacteria are stained with crystal violet dye

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2
Q

What is gram positive?

A

Class of bacteria which retains crystal violet - due to thick peptidoglycan layer

PURPLE COLOUR

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3
Q

What is gram negative?

A

Class of bacteria which do not retain crystal violet dye - Thin peptidoglycan layer sandwiched between inner and outer cell membrane

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4
Q

What is the outer membrane in gram negative organisms called?

A

Lipopolysaccharide (LPS) - which is anchored to peptidoglycan by lipoproteins

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5
Q

What are the main classes of bacteria by shape?

A
  • Cocci - spherical
    • Diplococcus - 2 cocci
    • Streptococcus - chain
    • Staphylococcus - cluster
  • Bacilli - rod shaped
  • Spirilli - spiral shaped
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6
Q

What is the capsule of a bacteria?

A

Polysaccharide layer that lies outside the cell envelope of some prokaryotes. It is considered a virulence factor. It can protect cells from phagocytosis, and can protect bacteria from desiccation.

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7
Q

What are flagellae?

A

Whip like structures that consist of helical filaments which help the bacteria rapidly propel themselves through different media.

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8
Q

What are fimbriae?

A

An appendage composed of curlin proteins that can be found on most gram positive bacteria and some gram negative bacteria. It is thinner and shorter than a flagellum. They are used to adhere to each other, animal cells, and inanimate objects.

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9
Q

What is a Plasmid?

A

Mobile, independent, self-replicating circular units of dsDNA. They carry genes that may benefit the organisms survival, and can frequently be transmitted between organisms by horizontal gene transfer.

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10
Q

What class of bacteria is S. Aureus?

A

Gram Positive Coagulase positive (has coagulase enzyme) Cocci

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11
Q

Can you name Gram positive coagulase negative Staphylococci?

A
  • S. hominis
  • S. epidermidis
  • S. Haemolyticus
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12
Q

What class of bacteria is S. Pneumoniae?

A

Gram positive, alpha-haemolytic cocci

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13
Q

What does alpha haemolysis mean?

A

Partial haemolysis

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14
Q

What class of bacteria is S. viridans?

A

Gram positive, alpha haemolytic cocci

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15
Q

What indicates partial haemolysis on blood agar plate?

A

Agar turns green - hydrogen peroxide produced by bacteria due to oxidation of haemoglobin to methoglobin

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16
Q

What is beta-haemolysis?

A

Complete haemolysis - turns blood agar clear

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17
Q

What does lancefield serotyping describe?

A

Specific carbohydrates present in the bacterial cell wall. Groups A, B and D are most clinically significant

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18
Q

What class of bacteria is S. Pyogenes?

A

Gram negative, beta haemolytic group A strep

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19
Q

What class of bacteria is S. agalactiae?

A

Gram positive, beta-haemolytic Group B strep

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20
Q

What can S. pneumoniae (Group A strep) cause?

A
  • Sore throats
  • Cellulitis
  • Necrotising fasciitis
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21
Q

What class of bacteria is E. Faecalis?

A

Gram positive, non-haemolytic group D strep

22
Q

What class of bacteria are enterococci?

A

Gram positive, non-haemolytic streptococci

23
Q

What class of bacteria is L. monocytogenes?

A

Gram positive, aerobic bacilli

24
Q

What class of bacteria is diptheria?

A

Gram positive, aerobic bacilli

25
Q

What class of bacteria is C. difficile?

A

Gram positive, anaerobic bacilli

26
Q

What class of bacteria is C. Perfringens?

A

Gram positive, anaerobic bacilli

27
Q

What class of bacteria is C. Tetani?

A

Gram positive, anaerobic bacilli

28
Q

What class of bacteria is N. meningitidis (meningococcus)?

A

Gram negative diplococcus

29
Q

What class of bacteria is N. gonorrhoae?

A

Gram negative diplococcus

30
Q

What class of bacteria is M. catarrhalis?

A

Gram negative cocci

31
Q

What class of bacteria is E. Coli?

A

Gram negative lactose fermenting bacilli

32
Q

What class of bacteria is S. enterica?

A

Gram negative, non-lactose fermenting bacilli

33
Q

What class of bacteria is S. typhi?

A

Gram negative bacilli

34
Q

What class of bacteria is Shigella?

A

Gram-negative bacilli

35
Q

What class of bacteria is K. pneumoniae?

A

Gram-negative, lactose fermenting bacilli

36
Q

What class of bacteria is Proteus spp.?

A

Gram negative bacilli

37
Q

What are coliforms?

A

Gram-negative bacilli which can ferment lactose with the production of acid and gas when incubated at 35–37°C. Normally found in the gut

38
Q

What class of bacteria are Campylobacter spp.?

A

Gram negative, S-shaped bacteria

39
Q

What class of bacteria is H. Pylori?

A

Gram Negative, curved rods

40
Q

What class of bacteria is H. Influenzae?

A

Gram Negative, cocco-bacilli

41
Q

What class of bacteria is Pseudomonas spp.?

A

Gram negative, aerobic bacilli

42
Q

What class of bacteria is Bacteriodes spp.?

A

Gram-negative, anaerobic bacilli

43
Q

What is the staining used to identify mycobacterium?

A

Ziehl-Neelsen Stain

44
Q

What is does a positive Ziehl-Neelsen Staining mean?

A

Resistant to decolourisation by acid or alcohol following carbol fuschin staining

45
Q

What is a Spirochaete?

A

Long, spiral shaped bacteria, which is most easily seen by immunoflourescence

46
Q

What class of bacteria is T. Pallidum?

A

Spirochaete

47
Q

What class of bacteria is borellia burgdoferri?

A

Spriochaete

48
Q

What class of bacteria is Leptospira?

A

Spirochaete

49
Q

What class of bacteria is Chlamydia trachomatis?

A

Gram negative ovoid bacteria

50
Q

What class of bacteria is Legionella pneumophila?

A

Gram-negative

51
Q
A