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LAST EXAMMMMMM Year I > micro-Bacterial taxonomy and virulence factors > Flashcards

micro-Bacterial taxonomy and virulence factors Flashcards

1
Q

What are the colors for gram stain and explain why they stain that way

A

+ is blue/dark purple because the crystal violet gets trapped in the thick peptidoglycan wall
- is red/pink because does not retain crystal violet from shield LPS layer though the alcohol disrupts membrane and so the safrinin stains

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2
Q

What catalyzes the stable cross linking of peptidoglycan and where is it located

A

transpeptidase in the inner cytoplasmic membrane

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3
Q

What Tx inhibits transpeptidase

A

penicillin

also called penicillin binding protein

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4
Q

What proteins are on the outer cell wall of gram +

A

teichoic acid, polysaccharides and other proteins

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5
Q

what do we detect in serologic studies on surface of gram +

A

teichoic acid

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6
Q

What are the layers of the gram - bacteria

A

cytoplasmic membrane
periplasmic space
peptidoglycan
LPS outer membrane

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7
Q

what is in the periplasmic space of gram -

A

proteins and enzymes

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8
Q

what lipoprotein is in the membrane of gram -

A

murein lipoprotein

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9
Q

What are the 3 components of LPS

A
  • outer carbohydrate chains 1-50 oligosaccharides that differ organism to organism (O sepcific side chain or O Ag)
  • core polysaccharide in the center part that is water soluble
  • Lipid A on the inside of core polysaccharide
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10
Q

What does Lipid A cause clinically? “endotoxin”

A

fever, diarrhea, and possibly septic shock

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11
Q

how do gram - bacteria get nutrients if LPS is barrier

A

porin proteins

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12
Q

What Antibiotics and chemicals break the peptidoglycan layer in gram +

A

penicillin and lysoyzmes

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13
Q

What are the 6 classic gram + organisms

A 
Staphcoccus
Streptococcus (enterococcus)
2 spore:
Bacillus Anthracis
Clostridium spp
non spore:
Corynebacterium
Listeria
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14
Q

What are the gram neg cocci?

A

N gonorrhea
Morazella
both are diplococci

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15
Q

What are the spirochetes?

A

gram neg
Treponema pallidum
Borrelia

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16
Q

How do you stain mycobacterium

A

acid fast.

slightly gram + sometimes

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17
Q

what type of microscope is needed to visualize spirochetes

A

dark field microscopy

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18
Q

what are periplasmic flagella and what organisms have them

A

flagella that run under outer membrane sheath

in spirochetes

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19
Q

Describe the membrane of mycoplasma

A

do not have cell wall. only simple cell membrane

neither gram + or -

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20
Q

What are the enterics

A 
E coli
Shigella
Salmonella
Yersinia
Klebsiella
Proteus
Enterobacter
Serratia
Vibrio
Campylobacter
Helicobacter
Pseudomonas
Bacteroides
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21
Q

What are the pleomorphic bacteria

A

Chlamydia and Rickettsia

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22
Q

Describe ribosomes of prokaryotes

A

70s subunits 50s and 30s

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23
Q

why are erythromyocin and tetracycline great antibiotics

A

E- attacks 50s ribosomes

T- attacks 30s ribosomes

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24
Q

What are the gram + obligate aerobes

A

nocardia

bacillus cereus

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25
Q

What does catalase break down

A

H2O2

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26
Q

What does peroxidase break down

A

H2O2

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27
Q

What does superoxide dismutase break down

A

superoxide radicals

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28
Q

What are the gram- obligate aerobes

A 
Neisseria
Pseudomonas
Bordetella
Legionella
Brucella
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29
Q

What are the Acid Fast obligate aerobes

A

mycobacterium and no cardia

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30
Q

what are the gram + facultative anaeriobes

A 
staph
bacillus anthracis
corynebacterium
listeria
actinomyces
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31
Q

What are the gram - facultative anerobes

A

most gram - rods

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32
Q

what are the gram + microaerophils

A

enterococcus

strep

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33
Q

what are the gram - microaerophils

A

spirochetes and campylobacter

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34
Q

what are the gram + obligate anaerobes

A

clostridium

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35
Q

what are the gram - obligate anaerobes

A

bacteroides

36
Q

what is the main difference of facultative anaerobes and microaerophils

A

facultative hace catalase and SOD, they also use O2 as acceptor in ETC
microaerophils use fermentation, no ETC and no catalase, only SOD

37
Q

what are chemoheterotrophs

A

use chemical and organic compounds for energy

38
Q

What is the definition of obligate intracellular organism? give e.g.

A

cannot make ATP, use host for energy source

chlamydia and rickettsia

39
Q

what spins the flagella on bacteria

A

the basal body that spans membranes

40
Q

what is a polar flagellum vs peritirchous

A

polar is at one end only

peritrichous is all around the cell

41
Q

What is the use of pili

A

adherence factors

42
Q

what bacteria uses AA instead of sugar for its capsule

A

bacillus anthracis

43
Q

What stains are used to visualize capsuled bacteria

A

india ink stain- crytptococcus fungus

quellung reaction Ab bind to capsule and the capsule will swell with water

44
Q

what immune response can take care of sugar capsules around bacteria

A

opsonization

45
Q

describe layer of endospores

A 
cell membrane
thick polypeptidoglycan mesh
cell membrane
wall of keratin like protein
outer layer called exosporium
46
Q

to best prevent the survival of endospores you must autoclave instruments for how long at what temp

A

15 min at 121 C

47
Q

What is a biofilm

A

a wall of polysaccharides secreted by some bacteria to protect themselves

48
Q

what is the best Tx against a biofilm on a prosthetic device

A

remove the device

49
Q

What are the facultative intracell organism

A 
Listeria
Salmonella
Yersinia
Francisella
Brucella
Mycobacterium
Legionella
Nocardia
Listen Sally Yer Friend Bruce Must Leave Now
50
Q

exotosins are primarily secreted by gram + or -

A

+ usually thought E coli and V cholera do as well

51
Q

What are examples of neurotoxins

A

botulinum and tetanus toxins

52
Q

how to enterotoxins work

A

inhibit NaCl resorption, activate NaCl secretion or kill epithelial cells

53
Q

What two manifestations do enterotoxins cause

A

infectious diarrhea

food poisoning

54
Q

food poisoning lasts for how long

A

12-24 hours. diarrhea and vomiting

55
Q

What are common culprits of food poisoning

A

S aureus

Baciilus cereus

56
Q

What is the classification of pyrogenic exotoxin and give organisms that secrete these

A

stimulate release of cytokines that cause rash, fever and TSS
S aureus
St pyogenes

57
Q

what are included as tissue invasive exotoxins

A

destroy DNA, collagen, fibrin, NAD RBC and WBC

58
Q

What bacteria have the AB toxins

A

B antrahcis, C botulinum

C tetani, C diphtheriae and V cholera

59
Q

what is bacteremia

A

bacteria in the blood

60
Q

What is sepsis

A

bacteremia that causes systemic immune response to the infection

61
Q

What is septic shock

A

dangerous drops in BP

organ dysfunction

62
Q

What is the most famous endogenous mediator of sepsis

A

TNF of cachetin

63
Q

What does tNF cause in sepsis

A

triggers release IL1

64
Q

What happens to vascular system in septic shock

A

vasodilation

Inc BP and organ hypoperfusion

65
Q

what happens to heart in septic shock

A

myocardial depression with dec CO and BP

organ hypoperfusion

66
Q

what happens to kidneys in septic shock

A

acute renal failure
dec urine output, volume overload
accumulation of toxins

67
Q

what happens to lungs in septic shock

A

ARDS hypoxia

68
Q

what happens to liver in septic shock

A

hepatic failure from accumulation of metabolic toxins and hepatic encephalopathy

69
Q

what happens to the brain in septic shock

A

encephalopathy

altered mental status

70
Q

what happens to coagulation pathway in septic shock

A

DIC

clotting and bleeding

71
Q

What is the mech of C. tetani

A

H (B) binds to neuronal gangliosides
L (A) blocks release of inhibitor NT
resulting in continuous motor activity

72
Q

What is the mech of C. botulinum

A

inhibit Ach release from motor neuron endplates

resulting in flaccid paralysis

73
Q

What is the mech of V cholera

A

5 B subunits bind GM1 gangliosides on intestinal cell membranes
2 A subunits carry out ADP ribosylation of GTP-binding protein activating cAMP
results in increased intraluminal NaCl which pulls fluid into intestinal tract

74
Q

What is the toxin of cholera

A

choleragen

75
Q

what is the toxin of E coli, Campylobacter jejuni and B cereus

A

heat labile toxin

76
Q

what toxin is common among E coli and Y enterocolitica

A

heat stabile toxin

77
Q

what is the mech of shigella

A

5 B subunits binding GI epithelium

A subunit inhibit protein synthesis by inactivating 60s

78
Q

What is characteristic of TSS

A

fever, rash, desquamation, diarrhea and hypotension

79
Q

What are the tissue invasive toxins of strep pyogenes

A 
hemolysins/Streptolysin O and S
Streptokinase
DNAases
Hyaluronidase
NADase
80
Q

What are the tissue invasive toxins of Staph aureus

A 
Lipases, penicillinase
staphylokinase
leukocidin
exofiliatin
factors that bind C'
81
Q

What toxin is responsible for scalded skin syndrome in children

A

exfoliatin

82
Q

What is the most lethal toxin of C perfringens

A

lecithinase which hydrolyzes membranes causing tissue destruction and gas gangrene

83
Q

What are the 3 components of anthracis

A

edema factor
lethal factor
protective Ag

84
Q

what is the mech of C diphth

A 
B binds hear and neural tissue
A: ADP ribosylates elongation factor EF2 inhibiting mRNA translation
causes: myocarditis
peripheral nerve palsies
CNS effects
85
Q

What is the mech of C difficile

A

toxin A causes fluid secretion and mucosal inflammation- diarrhea
toxin B causes cytotoxic to colonic epithelial cells
causes: pseudomembranous enterocolitis
diarrhea bloody, fever, abdominal pain

LAST EXAMMMMMM Year I (24 decks)

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