micro-Bacterial taxonomy and virulence factors Flashcards Preview

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Flashcards in micro-Bacterial taxonomy and virulence factors Deck (85):
1

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

+ 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

2

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

transpeptidase in the inner cytoplasmic membrane

3

What Tx inhibits transpeptidase

penicillin
also called penicillin binding protein

4

What proteins are on the outer cell wall of gram +

teichoic acid, polysaccharides and other proteins

5

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

teichoic acid

6

What are the layers of the gram - bacteria

cytoplasmic membrane
periplasmic space
peptidoglycan
LPS outer membrane

7

what is in the periplasmic space of gram -

proteins and enzymes

8

what lipoprotein is in the membrane of gram -

murein lipoprotein

9

What are the 3 components of LPS

-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

10

What does Lipid A cause clinically? "endotoxin"

fever, diarrhea, and possibly septic shock

11

how do gram - bacteria get nutrients if LPS is barrier

porin proteins

12

What Antibiotics and chemicals break the peptidoglycan layer in gram +

penicillin and lysoyzmes

13

What are the 6 classic gram + organisms

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

14

What are the gram neg cocci?

N gonorrhea
Morazella
both are diplococci

15

What are the spirochetes?

gram neg
Treponema pallidum
Borrelia

16

How do you stain mycobacterium

acid fast.
slightly gram + sometimes

17

what type of microscope is needed to visualize spirochetes

dark field microscopy

18

what are periplasmic flagella and what organisms have them

flagella that run under outer membrane sheath
in spirochetes

19

Describe the membrane of mycoplasma

do not have cell wall. only simple cell membrane
neither gram + or -

20

What are the enterics

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

21

What are the pleomorphic bacteria

Chlamydia and Rickettsia

22

Describe ribosomes of prokaryotes

70s subunits 50s and 30s

23

why are erythromyocin and tetracycline great antibiotics

E- attacks 50s ribosomes
T- attacks 30s ribosomes

24

What are the gram + obligate aerobes

nocardia
bacillus cereus

25

What does catalase break down

H2O2

26

What does peroxidase break down

H2O2

27

What does superoxide dismutase break down

superoxide radicals

28

What are the gram- obligate aerobes

Neisseria
Pseudomonas
Bordetella
Legionella
Brucella

29

What are the Acid Fast obligate aerobes

mycobacterium and no cardia

30

what are the gram + facultative anaeriobes

staph
bacillus anthracis
corynebacterium
listeria
actinomyces

31

What are the gram - facultative anerobes

most gram - rods

32

what are the gram + microaerophils

enterococcus
strep

33

what are the gram - microaerophils

spirochetes and campylobacter

34

what are the gram + obligate anaerobes

clostridium

35

what are the gram - obligate anaerobes

bacteroides

36

what is the main difference of facultative anaerobes and microaerophils

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

37

what are chemoheterotrophs

use chemical and organic compounds for energy

38

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

cannot make ATP, use host for energy source
chlamydia and rickettsia

39

what spins the flagella on bacteria

the basal body that spans membranes

40

what is a polar flagellum vs peritirchous

polar is at one end only
peritrichous is all around the cell

41

What is the use of pili

adherence factors

42

what bacteria uses AA instead of sugar for its capsule

bacillus anthracis

43

What stains are used to visualize capsuled bacteria

india ink stain- crytptococcus fungus
quellung reaction Ab bind to capsule and the capsule will swell with water

44

what immune response can take care of sugar capsules around bacteria

opsonization

45

describe layer of endospores

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

46

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

15 min at 121 C

47

What is a biofilm

a wall of polysaccharides secreted by some bacteria to protect themselves

48

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

remove the device

49

What are the facultative intracell organism

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

50

exotosins are primarily secreted by gram + or -

+ usually thought E coli and V cholera do as well

51

What are examples of neurotoxins

botulinum and tetanus toxins

52

how to enterotoxins work

inhibit NaCl resorption, activate NaCl secretion or kill epithelial cells

53

What two manifestations do enterotoxins cause

infectious diarrhea
food poisoning

54

food poisoning lasts for how long

12-24 hours. diarrhea and vomiting

55

What are common culprits of food poisoning

S aureus
Baciilus cereus

56

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

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

57

what are included as tissue invasive exotoxins

destroy DNA, collagen, fibrin, NAD RBC and WBC

58

What bacteria have the AB toxins

B antrahcis, C botulinum
C tetani, C diphtheriae and V cholera

59

what is bacteremia

bacteria in the blood

60

What is sepsis

bacteremia that causes systemic immune response to the infection

61

What is septic shock

dangerous drops in BP
organ dysfunction

62

What is the most famous endogenous mediator of sepsis

TNF of cachetin

63

What does tNF cause in sepsis

triggers release IL1

64

What happens to vascular system in septic shock

vasodilation
Inc BP and organ hypoperfusion

65

what happens to heart in septic shock

myocardial depression with dec CO and BP
organ hypoperfusion

66

what happens to kidneys in septic shock

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

67

what happens to lungs in septic shock

ARDS hypoxia

68

what happens to liver in septic shock

hepatic failure from accumulation of metabolic toxins and hepatic encephalopathy

69

what happens to the brain in septic shock

encephalopathy
altered mental status

70

what happens to coagulation pathway in septic shock

DIC
clotting and bleeding

71

What is the mech of C. tetani

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

72

What is the mech of C. botulinum

inhibit Ach release from motor neuron endplates
resulting in flaccid paralysis

73

What is the mech of V cholera

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

What is the toxin of cholera

choleragen

75

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

heat labile toxin

76

what toxin is common among E coli and Y enterocolitica

heat stabile toxin

77

what is the mech of shigella

5 B subunits binding GI epithelium
A subunit inhibit protein synthesis by inactivating 60s

78

What is characteristic of TSS

fever, rash, desquamation, diarrhea and hypotension

79

What are the tissue invasive toxins of strep pyogenes

hemolysins/Streptolysin O and S
Streptokinase
DNAases
Hyaluronidase
NADase

80

What are the tissue invasive toxins of Staph aureus

Lipases, penicillinase
staphylokinase
leukocidin
exofiliatin
factors that bind C'

81

What toxin is responsible for scalded skin syndrome in children

exfoliatin

82

What is the most lethal toxin of C perfringens

lecithinase which hydrolyzes membranes causing tissue destruction and gas gangrene

83

What are the 3 components of anthracis

edema factor
lethal factor
protective Ag

84

what is the mech of C diphth

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

85

What is the mech of C difficile

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