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Flashcards in Bacteriology Deck (92)
1

What stain used for Legionella?

Silver stain

2

How is Treponema visualized?

dark-field microscopy and fluorescent antibody staining

3

Intracellular bugs that are hard to stain?

Rickettsia, Chlamydia

4

How is Mycobacteria stained?

Acid-Fast stain due to high lipid conent; mycolic acids in cell wall detected by carbofuchsin

5

What is missing from mycoplasma?

cell wall

6

What bugs use a Giemsa stain?

Certain Bugs Really Try my Patience

Chlamydia, Borrelia, Rickettsia, Trypanosomes, Plasmodium

7

What does PAS (period-acid schiff) stain?

stains glycogen, mucopolysaccharides

8

What is PAS used to diagnose?

Whipple disease - Tropheryma whipplei

9

What is India Ink used to stain?

Crypotcoccus neoformans (mucicarmine can also be used to stain thick polysaccharide capsule red)

10

What is Silver stain use for?

Legionella, Fungi (pneumocystis), helicobacter pylori

11

what bacterial structure protects against phagocytosis?

capsule (organized, discrete polysaccharide layer, except in Bacillus anthracia, contains D-glutamate)

12

what helps with binding to foreign surfaces?

glycocalyx (loose network of polysaccharides)

13

What composes the outer membrane?

endotoxin - Lipopolysaccharide (LPS); major suface antigen

14

where are beta-lactamases contained?

in the periplasmic space between cytoplasmic membrane and outer membrane

15

in what bugs is periplasmic space present?

gram-negative bacteria

16

What agar do use for H. flu?

chocolate agar

17

what agar do use for Neisseria species?

Thayer-Martin

18

what agar for B. pertussis?

Bordet-Gengou agar OR Regan-Lowe medium

19

what agar for C. diphtheriae?

Tellurite agar, Loffler medium

20

what agar for M. tuberculosis?

Lowenstein-Jensen agar

21

what agar for Mycoplasma pneumonia?

Eaton agar

22

what agar for Lactose-fermenting enterics?

MacConkey agar (colonies turn pink because of fermented acid)

23

what agar for E. coli?

Eosin-methylene blue (EMB) agar (colonies with green metallic sheen)

24

what agar for Legionella?

charcoal yeast extract agar buffered with cysteine and iron

25

what agar for fungi?

Sabouraud agar

26

Examples of Anaerobes and properties?

Fusobacterium, Clostridium, Bacteroides, Actinomyces

lack catalase and/or superoxide dismutase and susceptible to oxidative damage
FOUL SMELLING

27

What antibiotic does NOT work against anaerobes?

Aminoglycosides (require O2 to get into bacteria)

28

What are the obligate intracellular bugs?

Rickettsia, Chalmydia, Coxiella

29

What are the facultative intracellular bugs?

Some Nasty Bugs May Live FacultativeLY

Salmonella
Neisseria
Brucella
Mycobacterium
Listeria
Francisella
Legionella
Yersinia pestis

30

what are encapsulated bacteria?

SHiNE SKiS

Strep pneumo
H. flu
Neisseria meningitidis
E. coli
Salmonella
Klebsiella
group b Strep

31

what of encapsulated bacteria have vaccines?

strep pneumo, H. flu, N. meningitidis

32

how are encapsulated bacteria cleared?

opsonized and then cleared by the spleen

33

what are urease + bugs?

CHuck norris hates PUNKSS

Cryptococcus
H. pylori
Proteus
Ureaplasma
Nocardia
Klebsiella
S. epidermidis
S. saprophyticus

34

what are catalase + bugs?

CATs Need PLACESS to hide

CAT = catalase +
Nocardia
Pseudomonas
Listeria
Aspergillus
Candida
E. coli
Staphylococci
Seratia

35

What pigment does Actinomyces produce?

yellow sulfur granules

36

what pigment does S. aureus produce?

yellow pigment (aureus = gold)

37

what pigment does Pseudomonas produce?

blue-green pigment

38

what pigment does Serratia marcescens produce?

red pigment (maraschino cherry)

39

what bug expresses protein A and what is function?

staph aureus and to prevent opsonization and phagocytosis

40

what bugs express IgA protease?

SHiN

strep pneumo
H. flu
Neisseria

to help colonize mucosa

41

What bug expresses M protein and what is purpose?

group A strep

prevent phagocytosis (molecular mimicry)
possible mech associated with rheumatic fever and autoimmune response

42

what exotoxin does C. diphtheriae produce?

diphtheria toxin

43

what does diphtheria toxin do?

inactivates elongation factor (EF-2)

44

How does diphtheria manifest?

pharyngitis with pseudomembranes in throat
severe lymphadenopathy (bull neck)

45

what exotoxin does Pseudomonas aeruginosa produce?

exotoxin A

46

what does exotoxin A do?

inactivates elongation factor (EF-2)

47

what does exotoxin A cause?

host cell death

48

what two exotoxins inhibit elongation factor (EF-2)?

diphtheria toxin (C. diphtheriae)
exotoxin A (P. aeruginosa)

49

what exotosin does Shigella produce?

Shiga toxin

50

what does shiga toxin do?

inactivates the 60S ribosome by removing adenine from rRNA

51

how does Shigella present?

Gi mucosal damage --> dysentery
ST also enhances cytokine release, causing hemolytic-uremic syndrome (HUS)

52

what bugs can cause HUS?

Shigella, EHEC serotype O157:H7

53

what exotoxin does enterohemorrhagic E. coli produce?

Shiga-like toxin (SLT)

54

how does Shiga-like toxin work?

inhibits the 60S ribosome by removing adenine from rRNA

55

how does enterohemorrhagic E. coli present?

SLT enhances cytokine release, causing HUS (protypically in EHEC serotype O157:H7

EHEC does NOT invade host cells

56

what exotoxin does Entertoxogenic E. coli produce?

heat-labile toxin (LT) or heat-stabile toxin (ST)

57

how does heat-labile toxin work?
how does heat-stable toxin work?

LT - overactivates adenylate cyclase (increase cAMP) --> increased Cl- secretion in gut and water efflux

ST - overactivates guanylyl cyclase (increase cGMP) --> decreased reabsorption of NaCl and water in gut

58

How does ETEC present?

watery diarrhea

59

What exotoxin does B. anthracis produce?

Edema toxin

60

How does edema toxin work?

mimics the adenylate cyclase enzyme (increase cAMP)

61

How does Bacillus anthracis present?

characteristic edematous borders of black eschars in cutaneous anthrax

62

What exotoxin does vibrio cholerae produce?

cholera toxin

63

how does cholera toxin work?

overactivates adenylate cyclase (increase cAMP) which permanently activates Gs --> increased Cl- secretion in gut and H2O efflux

64

how does cholera present?

voluminous "rice-water" diarrhea

65

what exotoxin does Bordetella pertussis produce?

Pertussis toxin

66

how does pertussis toxin work?

overactivates adenylate cycle (increase cAMP) by disabling Gi, impairing phagocytosis to permit survival of microbe

67

how does pertussis present?

WHOOPING COUGH
- cough on expiration and whoop on inspiration

68

What exotoxin does Clostridium tetani produce?
What exotoxin does Clostridium botulinum produce?

Tetanospasmin toxin
Botulinum toxin

69

How does tetanospasmin and botulinum work?

proteases that cleave SNARE (which are normally required for NT release)

70

How does tetanus present?

spasticity
risus sardonicus
"lockjaw"

Toxin prevents release of inhibitory (GABA and glycine) NTs from Renshaw cells in spinal cord

71

How does botulism present?

Flaccid paralysis, floppy baby

toxin prevents release of stimulatory (ACh) signals at neuromuscular junction --> flaccid paralysis

72

What exotoxin does Clostridium perfringens produce?

Alpha toxin

73

How does alpha toxin work?

phospholipase (lecithinase) that degrades tissue and cell membranes

74

how does C. perfringens present?

degradation of phospholipids --> myonecrosis ("gas gangrene") and hemolysis ("double zone") on blood agar

75

what toxin does strep pyogenes produce?

streptolysin O
exotoxin A

76

how does streptolysin O work?
how does exotoxin A work?

protein that degrades cell membrane

binds to MCH II and TCR outside of antigen binding site to cause overwhelming release of IL-1, IL-2, IFN-gamma, and TNF-alpha --> shock

77

How does S. pyogenes present?

lyses RBCS; contributes to beta-hemolysis

host antibodies against streptolysin used to diagnose rheumatic fever

with exotoxin A --> toxic shock syndrome: fever, rash, shock

78

What exotoxin does Staph aureus produce?

Toxic shock syndrome toxin (TSST-1)

79

how does TSST-1 work?

binds to MCH II and TCR outside of antigen binding site to cause overwhelming release of IL-1, IL-2, IFN-gamma, and TNF-alpha --> shock

80

what endotoxin is the most toxic?

LPS found on gram-negative bacteria

81

what does LPS endotoxin cause systemically?

ENDOTOXIN

Edema
Nitric oxide
DIC/Death
Outer membrane
Tnf-alpha
O-antigen
Xtremely heat stable
Il-1
Neutrophil chemotaxis

82

How to determine between Staphylococci using Novobiocin

Saprophyticus is resistant
Epidermidis is sensitive

83

How to determine between Streptococci using Optochin

Viridans is resistant
pneumonia is sensitive

84

How to determine between Streptococci using Bacitracin

group B strep are resistant
group A strep are sensitive

85

alpha-hemolytic bacteria

green ring around colonies on blood agar
S. pneumo or viridans strep

86

What are S. pneumo staining findings?

Gram +
Catalase -
Alpha-hemolytic
Optochin sensitive

87

What are Viridans Strep staining findings?

Gram +
Catalse -
Alpha-hemolytic
Optochin resistant

88

Beta-hemolytic bacteria

clear area of hemolysis

S. aureus, Listeria

S. pyogenes, S. agalactiae
- differentiate these two via bacitracin

89

what are S. aureus staining findings?

Gram +
Catalase +
Coagulase +
Beta-hemolytic

90

What are S. pyogenes staining findings?

Gram +
Catalase -
beta-hemolytic
Bacitracin sensitive

91

What are S. agalactiae staining findings?

Gram +
Catalase -
beta-hemolytic
Bacitracin resistant

92

Listeria presentation?

tumbling motility
meningitis in newborns
unpasteurized milk