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Flashcards in Micro. Deck (84):
1

peptidoglycan - 2 functions

1) gives rigid support
2) protects against osmotic pressure

2

cell wall function

major surface antigen - induces TNF and IL-1

3

outer membrane (gram -) functions

site of endotoxin (LPS), major surface antigen
Lipid A induces TNF and IL-1
O polysaccharide is the antigen

4

plasma membrane function

site of oxidative and transport enzymes

5

what ribosomes do bacteria have vs. eukaryotes

bacteria: 30S + 50S = 70S
eukaryotes: 40S + 60S = 80S

6

periplasm - location and what it stores

location: between outer membrane and cytoplasmic membrane in gram - bacteria
Stores: hydrolytic enzymes such as beta-lactamases

7

what are pilus and fimbrae made of

glycoprotein

8

what is a flagellum made out of

protein

9

spore - what is it resistant to, what is it made out of

resistant to: dehydration, heat, chemicals
made out of: keratin-like coat, dipicolinic acid, peptidoglycan

10

capsule - function

protects against phagocytosis

11

quellung reaction

used to see if a bacterium is encapsulated

12

glycocalyx function

mediates adherence to surfaces, especially foreign surfaces (indwelling catheter)
either a capsule or a biofilm/slime - difficult to remove from surfaces

13

enzyme that crosslinks the peptide side chains in peptidoglycans

transpeptidase

14

bugs that do not gram stain well + reason why

These Microbes May Lack Real Color

Treponema: too thin to be visualized
Mycobacteria: high lipid content
Mycoplasma: no cell wall
Legionella: intracellular - branched chain fatty acids in cell wall do not stain well
Rickettsia: intracellular parasite
Chlamydia: intracellular parasite - lacks classic peptidoglycan because of low muramic acid

15

How to visualize treponema?

dark field microscopy

16

How to visualize legionella?

silver stain

17

What bugs can you visualize with Giemsa?

Certain Bugs Really Try My PaSHience

C: chlamydia
B: borrelia
R: Rickettsia
T: trypanosomes --> t. cruzi
P: plasmodium
H: histoplasma

18

PAS (periodic acid schiff) stains what and what organisms can be visualized?

stains: glycogen and mucopolysaccharides
diagnose: Whipple disease - tropheryma whipplei

19

Ziehl Neelsen (carbol fushsin) helps visualize what organisms

Acid fast bacteria: nocordia, mycobacteria, protozoa (cryptosporidium oocyts)

20

What is the alternative to Ziehl Neelsen and how does it compare?

Auramine/rhodamine stain for screening
inexpensive, more sensitive, less specific

21

India ink can be used to visualize which organisms?

cryptococcus neoformans

22

mucicarmine stain

stains red- really just used for cryptococcus neoformans or mucin (some cancers produce mucin)

23

Silver stain is used to visualize which organisms?

fungi (pneumocystis), legionella, helicobacter pylori

24

H. influenzae requires what culture

Chocolate agar

25

N. gonorrhea/meningitis requires what culture

Thayer martin

26

B. pertussis requires what cultures

Bordet Gengou
Regan Lowe

27

C. diphtheria requires what culture

Tellurite agar, Loffler medium

28

M. tuberculosis requires what culture

Lowenstein-Jensen

29

M. pneumoniae requires what culture

Eaton agar

30

Lactose-fermenting enterics require what culture

MacConkey agar

31

E. coli requires what culture:

Eosin-methylene blue (EMB) agar

32

Legionella requires what culture

Charcoal yeast extract agar buffered with cysteine and iron

33

Fungi require what culture

Sabouraud agar

34

Chocolate agar contains what

Factors V (NAD+) and X (hematin)

35

Thayer Martin contains what

Very Typically Cultures Neisseria

Vancomycin, Trimethoprim, Colistin, Nystatin

36

Colistin inhibits what?

inhibits gram - except Neisseria

37

Bordet-Gengou agar contains what

potatoe

38

Regan Lowe medium contains what?

Charcoal, blood, and antibiotic

39

Eaton agar requires what?

cholesterol

40

MacConkey agar turns what color and why?

Fermentation produces acid, which causes colonies to turn pink

41

What colors do EMB agar colonies turn?

colonies have a green metallic sheen

42

Chocolate agar cultures what organisms?

h. influenze

43

Thayer Martin agar cultures what organisms?

Neisseria gonorrhea/meningitidis

44

Bordet Gengau agar cultures what organisms?

B. pertussis

45

Regan-Lowe medium cultures what organisms?

B. pertussis

46

Tellurite agar, Loffler medium cultures what organisms?

C. diphtheriae

47

Lowenstein Jensen agar cultures what organisms?

M tubercululosis

48

Eaton agar cultures what organisms?

M. pneuoniae

49

MacConkey agar cultures what organisms?

Lactose fermenting enterics

50

EMB agar cultures what organisms?

E. coli

51

Charcoal yeast extract agar buffered with cysteine and iron cultures what organisms?

Legionella

52

Sabuouraud agar cultures what organisms?

fungi

53

aerobic organisms:

Nagging Pests MustBreathe

Nocardia
Pseudomonas aeruginosa
MycoBacterium tuberculosis

54

Anaerobic bacteria lack what enzyme(s)

Catalase and/or superoxide dismutase - makes them susceptible to oxidative damage

55

Three general features of anaerobic bacteria:

1) foul smelling (short chain fatty acids)
2) difficult to culture
3) produce gas in tissue (CO2 and H2)

56

Where are anaerobes normal flora in the body?

GI tract

57

What antibiotic is resistant to anaerobes and why?

Aminoglycosides because they require O2 to enter the bacterial cell

58

What bacteria are anaerobes?

Frankly Can't Breathe Air

Fusobacterium
Clostridium
Bacteroides
Actinomyces

59

Obligate intracellular bugs:

[stay inside when it is] Really COld and CHilly

Rickettsia
COxiella
CHlamydia

60

Why are obligate intracellular bugs obligate intracellular?

rely on host ATP

61

Facultative intracellular bugs:

Some Nasty Bugs May Live FacultativeLY

Salmonella
Neisseria
Brucella
Mycobacterium
Listeria
Francisella
Legionella
Yersinia Pestis

62

Encapsulated organisms:

SHiNE SKiS

Salmonella typhi
Haemophlius influenzae type B
Neisseria meningitidis
E. coli

Strep pneumoniae
Klebsiella pneumoniae
group B Strep (agalactiae)

63

Urease postive organisms:

CHunk PUNKSS

Cryptococcus
H pylori
Proteus
Ureaplasma
Nocardia
Klebsiella
Staph epidermidis
Staph saprophyticus

64

Catalase positive organisms:

Cats Need PLACESS

(Catalase)
Nocardia
Psuedomonas
Listeria
Aspergillus
Candida
E. coli
Staphylococci
Serratia

65

Actinomyces israelli color

yellow sulfur granules - composed of filaments of bacteria

66

S. aureus pigment

yellow pigment

67

Pseudomonas aeruginosa pigment

blue green pigment

68

Serratia marcescens pigment

red pigment

69

Corynebacterium diphtheria toxin and MOA

diphtheria toxin
Inactivates EF2 via ADP ribosylation

70

Pseudomonas aeruginosa toxin and MOA

Exotoxin A
Inactivates EF2 via ADP ribosylation

71

Shigella toxin and MOA

Shiga-toxin
Inactivates 60S ribosome by removing adenine from rRNA (inhibits protein synth)

72

EHEC toxin and MOA

Shiga-like toxin (SLT) - inactivates 60S ribosome by removing adenine from rRNA (inhibits protein synth)

73

ETEC toxin and MOA

Heat labile toxin & heat stable toxin

HLT: overactivates adenylate cyclase, increasing cAMP, increasing Cl- secretion in gut and water efflux

HST: overactivates guanylate cyclase, increasing cGMP, decreasing reabsoprtion of NACL and H20 in gut

74

Bacillus anthracis toxin and MOA

edema toxin
mimics adenylate cyclase enzyme, increasing cAMP

75

Vibrio cholera toxin and MOA

cholera toxin
Overactivates adenylate cyclase (increasing cAMP) by permanently activating Gs - increases Cl- secretion in gut and H20 efflux

76

Bordatella pertussis toxin and MOA

pertussis toxin
Overactivates adenylate cyclase (increasing cAMP) by disabling Gi = impairing phagocytosis to permit survival of microbe

77

clostridium tetani toxin and MOA

Tetanospasmin
Protease that cleaves SNARE - prevents release of inhibitory neurotransmitters (GABA and glycine) from Renshaw cells in spinal cord

78

clostridium botulinum toxin and MOA

botulinum toxin
protease that cleaves SNARE - prevents release of stimulatory Ach neurotransmitter that signals at NMJ

79

clostridium perfringens toxin and MOA

alpha toxin
phosphlipase (lecithinase) that degrades tissue and cell membranes

80

Strep pyogenes toxin and MOA

Streptolysin O
Protein that degrades cell membranes

81

staph aureus toxin and MOA

Toxic shock syndrome toxin 1
Binds to MHC II and TCR outsie of antigen binding site to cause overwhelming release of IL-1, IL-2, IFN gamma, and TNF-alpha

82

strep pyogenes superantigen toxin and MOA

exotoxin A
Binds to MHC II and TCR outsie of antigen binding site to cause overwhelming release of IL-1, IL-2, IFN gamma, and TNF-alpha

83

What do spores have in their core?

dipicolinic acid

84

How do you kill spores

must autoclave to potentially kills pores (steam at 121 degrees for 15 minutes)