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Flashcards in Bacterial structure Deck (135):
1

cell wall - chemical composition

peptidoglican: sugar back bone with peptide side side chains cross-linked by transpeptidase

2

cell wall - function

1. gives rigid support
2. protects against osmotic pressure
3. major surface antigen

3

lipotechoic acid -->

induce TNF and IL-1

4

lipotechoic acid - area

Gram-positive bacteria
anchored to cytoplasmic membrane --> through the cell wall

5

bacteria with outer membrane / function / structure

gram (-)
function: 1. site of endotoxin (LPS) 2. major antigen surface (outer membrane proteins) 3. porins: transport accross outer membrane
structure: outer leaflet (endotoxins and embedded proteins), inner leaflet (phospholipids)

6

LPS - is composed by

Lippid A (inner)
O polysaccharide (outer)

7

LPS - function

Lipid A --> induce TNF and IL-1
O polysaccharide --> antigen

8

bacteria with LPS (and location)

gram (-) (outer membrane)

9

bacterial plasma membrane - structure

phospholipid bilayer with embedded proteins (penicillin-binding proteins) and other enzymes
lipotechoic acid (only gram +)

10

bacterial plasma membrane - function

site of oxidative and transport enzyme

11

function of ribosomes / composed by (in bacteria)

protein synthesis (50s and 30s)

12

bacterial periplasm?

space between the cytoplasmic membrane and outer membrane in gram (-) bacteria (peptidoglycan in middle)

13

bacterial periplasm function

contains many hydrolytic enzymes, including β-Lactamases

14

Pilus/firia function

1. mediate adherence of bacteria to cell surface
2. sex pilus forms attachment between 2 bacteria during conjunction

15

Pilus/firia - chemical composition

glycoprotein

16

bacterial spore - characteristics

resistant to dehydration, heat and chemicals

17

bacterial spore - chemical composition

1. keratin like - coat
2. dipicolinic acid
3. peptidoglycan
4. DNA

18

plasmid contain variety of genes for

1. antibiotic resistance
2. enzymes
3. toxins

19

bacterial capsule - function

protects against phagocytosis

20

bacterial capsule - chemical composition

Organized, discrete polysaccharide layer except Bacillus antrhacis wich contains D-glutamate

21

bacterial capsule - Organized, discrete polysaccharide layer (except Bacillus antrhacis wich contains D-glutamate

Bacillus antrhacis wich contains D-glutamate

22

bacterial glycocalyx - function

mediates adherence to surfaces, especially foreign surface

23

bacterial glycocalyx mediates adherence to surfaces, especially foreign surface - example

indwelling catheters

24

bacterial glycocalyx is composed by

a loose network of polysaccharides

25

bacterial structure - what is unique for gram (+)

Lipotechoic acid

26

bacterial structure - what is unique for gram (-)

1. Porins on outer mambrane
2. outer membrane
3. endotoxin/LPS
4. periplasmic space

27

gram + with endotoxin/LPS

Listeria monocytogenes

28

flagellum - gram + or - ? / function / chemical composition ?

both
function: motility
chemical composition: protein

29

peptidoclycan is AKA

murein

30

bacterial taxonomy - groups according to morphology

1. spherical (coccus)
2. rob (bacillus)
3. Branching filamentous
4. Pleomorphic
5. spiral
6. no cell wall

31

bacterial taxonomy - spherical and rob AKA

spherical --> coccus
rob --> bacillus

32

bacterial taxonomy - gram + coccus

1. staphylococcus
2. streptococcus

33

bacterial taxonomy - gram - coccus

1. Moraxella catarrhalis
2. Neisseria

34

bacterial taxonomy - gram negative robs are divided to (according to their action/origin)

1. enterics
2. respiratory
3. zoonotic

35

bacterial taxonomy - branching filamentous bugs and gram?

gram +
1. actinomyces
2. nocardia

36

bacterial taxonomy - pleomorphic - gram and bugs ?

gram -
1. chlamydiae
2. Rickettsiae

37

bacterial taxonomy - spiral - bags and gram?

gram -
spirochetes (Borrelia, Leptospira, Treponema)

38

respiratory gram negative robs?

1. Bordetella
2. Haemophilus
3. Legionella
4. Burkholderia cepacia

39

zoonotin gram negative robs?

1. Bartonella
2. Brucella
3. Francisella
4. Pasteurella

40

bacterial taxonomy - no cell walls

1. Mycoplasma
2. ureoplasma

41

bacteria with no cell wall - special characteristic

contain sterols, which do not gram stain

42

how do bacterial cell membranes differ from mammalian cell membranes

Bacterial cell membranes lack sterols (except Mycoplasma, Ureaplasma)

43

Gram stain limitations for bugs means

these bugs do not gram stain well

44

Gram stain limitations - bugs?

Mnemonic: These Microbes May Lack Real Color
Treponema (and leptospura)
Mycobacteria (and ureoplasma)
Legionella pneumonophila
Rickettsia
Chlamydia
(+ BARTONELLA, ehrlichia, anaplasma)

45

Gram stain limitations - treponema - mechanism

too thin to be visualized

46

Gram stain limitations - Mycoplasma - mechanism

no cell wall

47

Gram stain limitations - legionella pneumophila - mechanism

primarily intracellular

48

Gram stain limitations - Rickettsia - mechanism

intracellular parasite

49

Gram stain limitations - Chlamydia - mechanism

1. intracellular parasite
2. lacks classic peptidoglycan because of low muramic acid

50

how to see treponemes

dark field microscopy
and
fluorescent antibody staining

51

microbiology - types of stains

1. Giemsa
2. PAS
3. Ziehl-Neelsen
4. India INK
5. Silver stain

52

Giemsa stain - microbes?

Mnemonic - Certain Bugs Really TRY my Patience
Chlamydia
Borrelia
Rickettsia
TRYpanosomes
Plasmodium

53

PAS stain? (means) / (which substance)

periodic acid-Schiff
1. glycogen
2. mucopolysaccharides

54

PAS is used to

diagnose Whipple disease (Tropheryma Whipplei)

55

Ziehl-Neelsen (carbol fuschin) stains

Acid-Fast bacteria (Nocardia, Mycobaceria) and protozoa (Cryptosporidium oocysts)

56

protozoa that are stained by Ziehl-Neelsen

Cryptosporidium oocysts

57

Ziehl-Neelsen - alternative stain?

auramine - rhbamine stain

58

auramine - rhbamine stain is Ziehl-Neelsen alternative for ... (why)

screening (inexpensive, more sensitive but less specific)

59

mycobacteria - special characteristic of the structure (and clinical relevance)

cell wall are high in mycolic acid - detected by carbolfuchin in acid-fast stain

60

india ink stains

Cryptococcus neoformans

61

Cryptococcus neoformans is stained by

1. India ink
2. Mucicarmine

62

Cryptococcus neoformans - mucicarimine - mechanism

stain thick polysaccharide capsule red

63

silver stain is used to stain

1. Fungi (eg. Pneumocytosis)
2. Legionella
3. Helicobacter pylori

64

Special culture requirements - H. influenza - media (and its contains)?

Chocolate agar - Factor V (NAD+) and X (hematin)

65

Special culture requirements - Neisseria - media (and its contains)?

Thayer - Martin - vancomicin , trimethoprim, colistin , nystatin

66

Thayer - Martin contains ... (and action)

1. vancomicin --> inhibits gram (+)
2. trimethoprim
3. colistin --> inhibits gram (-) except Neisseria
4. nystatin --> inhibits fungi

67

Special culture requirements -Bordetella Pertussis - media (and its contains)?

1. Bordet-Gengou agar (potato)
2. Regan-Lowe medium (Charcoal, blood, antibiotic)

68

Special culture requirements - Corynebacterium diphtheriae - media ?

Tellurite agar and Loffler medium

69

Special culture requirements - Mycoplasma Pneumoniae - media (and its contains)?

Eaton agar --> cholesterol (because Mycoplasma requires sterols)

70

Mycoplasma - special charactersitics

no cell wall
contains sterols

71

Special culture requirements - Lactose-fermenting enterics - media?

MacConkey agar

72

MacConkey agar - mechanism

Lactose fermenting enterics --> fermentation produce acid causing colonies to turn PINK

73

Special culture requirements - E-coli - media?

1. Eosin methylene blue (EMB) agar
2. it also lactose fermenting (not all strains)

74

E-coli in Eosin methylene blue agar -->

colonies with green metallic sheen

75

Special culture requirements - Legionella - media?

charcoal yeast extract agar buffered with cysteine and iron

76

Special culture requirements - Fungi - media?

Sabouraud agar

77

Bordet-gengou agar - bugs

Bordetella Pertussis

78

Special culture requirements - Mycobabterium Tuberculosis - media?

Lowenstein-Jensen agar

79

media with charcoal, blood, antibiotis (and bugs)

Regan-Powe medium - Bordetella Pertussis

80

Sabouraud agar - bugs

Fungi

81

Chocolate agar - contains and bugs

contains V (NAD+) and X (hematin)
H. influenzae

82

potato agar? (and bug)

Bordet-Gengou agar
Bordetella Pertussis

83

colonies with green metallic sheen - media and bug

Eosin methylene blue (EMB) agar
E-coli

84

charcoal yeast extract agar buffered with cysteine and iron - bug?

Legionella

85

bacteria are divided to ... (according to O2 use)

1. aerobes
2, anaerobes

86

aerobes bacteria - mechanism

use an O2 dependent system to generate ATP

87

aerobes bacteria - examples (3)

1. Nocardia
2. Pseudomonas
3. Mycobacterium Tuberculosis

88

factors that induce M. Tuberculosis reactivation

1. immunocompromise
2. TNF-α inhibitors

89

Reactivation of M. Tuberculosis has a predilection for the .... (location) (why)

apices of the lung, which have the highest PO2

90

anaerobe bacteria - examples (4)

1. fusobacterium
2. Clostiridium
3. Bacteroids
4. Actinomyces

91

anaerobe bacteria lack ..... and thus ....

catalase and/or superoxide dismutase and thus susceptible to oxidative damage

92

anaerobes - smelling (and mechanism)

foul smeling - short (volatile short-chain fatty acids)

93

anaerobes - culturing

very difficult

94

anaerobes prodce

gas in tissue (CO2 and H2)

95

anaerobes in the body

normal flora in GI tract
typically pathogenic elsewhere else

96

anaerobes and aminoglycosides

aminoglycosides are ineffective against anaerobes because these antibiotics require 02 to enter into bacterial cell

97

Intracellular bugs are divided to

1. Obligate intracellular
2. Facultive intracellular

98

Obligate intracellular bugs - characteristic and bugs

rely on host ATP
1. Rickettsia
2. Chlamydia
3. Coxiella

99

Facultive intracellular - bugs?

1. Salmonella 2. Neisseria 3. Brucella 4. Mycobacterium
5. Listeria 6. Francisella 7. Legionella 8. Yersinia pestis

100

Encapsuled bacteria - examples

1. Streptococcus pneumoniae
2. Haemophilus influenzae type B
3. Neisseria meningitidis
4. E. coli
5. Salmonella
6. Klebsiella pneumoniae
7. group B strep

101

Encapsuled bacteria - their capsule serve as an

anthiphagocytic viruence factor

102

Encapsuled bacteria - clinically relevance

1. capsule + protein conjugate serves an as antigen in vaccines
2. Are opsonized and then cleared by spleen (so increased risk for severe infection in asplenics)

103

Encapsuled bacteria - asplenic

asplenic have decreased opsonizing ability and thus high risk for severe infections

104

asplenic patients - vaccines?

1. S. pneumoniae
2. H. influenzae type B
3. N. meningitidis

105

Encapsuled bacteria - vaccines mechanism

Some vaccines containing polysaccharide capsule antigens are conjugated to a carrier protein, enchancing immunogenicity by promoting T-cell activation and subsequent class switching.

106

asplenic patients - vaccines - structure

1. S. pneumoniae --> PCV conjugate, PPSV non congugate
2. H. influenzae type B--> conjugate
3. N. meningitidis --> conjugate

107

S pneumoniae - vaccines and structure

PCV - pneumonococcal congugate vaccine (Prevnar)
PPSV - pneumonococcal polysaccharide vaccine with no congugate protein (Pneumovax)

108

Urease-positive organisms / action of urease

1. Cryptococcus
2. H. pylori
3. Proteus
4. Ureoplasma
5. Nocardia
6. Klebsiella
7. S. epidermidis
8. S. saprophyticus
UREA --> ammonia + CO2 (high ph) --> ammoniun magnesium phosphate stone

109

bacterial catalase - mechanism

degrades H2O2 into H20 and bubbles of O2 before it can be converted to microbicidal products products by the enzyme peroxidase

110

Chronic granoulomatous disease - pathophysiology

NADPH oxidase deficiency

111

NADPH oxidase - action

O2 + NADPH --> NADP+ + O2- (superoxide anion)

112

people with Chronic granoulomatous disease have recurrent infection of with .... (why)

CATALASE + organism
even without NADPH they can convert H2O2 produced by bacteria
CATALASE + organism degrade their H2O2

113

CATALASE + organism - examples

PLACESS (+ nocardia, H. pylori, B. cepacia
1. Staphylococci 2. E-coli 3. Candida
4. Serratia 5. Listeria 6. Aspergillus
7. Pseudomonas 8. Nocardia

114

Catalase + non bacterial organisms?

1. Candida
2. Aspergillus

115

Pigmented - producing bacteria / pigmented?

1. Staphylococcus aureus --> yellow
2. Pseudomonas aeroginosa --> blue green
3. Serratia marcencens --> red
4. Actinomyces israelli --> yellow "sulfur" granules

116

Bacterial virulence factors - action

promote evasion of host immune response

117

Bacterial virulence factors - types

1. Protein A
2. IgA protease
3. M protein

118

Bacterial virulence factors - Protein A is expressed by

Staphylococcus aureus

119

Bacterial virulence factors - Protein A?

Binds Fc region of IgG --> prevent opsonization and phagocytosis

120

Bacterial virulence factors - IgA protease is secreted by

1. S. pneumoniae
2. H. influenzae type B
3. Neisseria

121

Bacterial virulence factors - IgA protease - action

enzyme that cleaves IgA, in order to colonize respiratory mucossa

122

Bacterial virulence factors - M Protein is expressed by

group A streptococci

123

Bacterial virulence factors - M Protein - action

Helps prevent phagocytosis

124

Bacterial virulence factors - M Protein - clinical relevance

Share similar epitopes to human cellular proteins (protein mimicry --> possibly underlines the autoimmune response in acute rheumatic fever

125

Bacterial virulence factors - types and expression by

1. Protein A --> S. aureus
2. IgA protease --> S. pneumoniae, H. influenzae type B, Neisseria
3. M protein --> group A streptococci

126

Type III secretion system is AKA

injectisome

127

Type III secretion system (injectisome)

''Needle-like'' protein appendage facilitating direct delivery of toxins from certain gram (-) bacteria INTO eukaryotic host cell

128

Type III secretion system (injectisome) - which bacteria (and example)

certain gram (-) bacteria
example: pseudomonas, Salmonella, Shigella, E-coli

129

spore forming bacteria - bugs and diseases

1. Bacillus antrhacis --> antrax
2. Bacillus cereus --> Food poisoning
3. Clostiridium botulinum --> botulism
4. Clostiridium difficile --> Antibiotic associated colitis
5. Clostiridium perfingess --> gas gangrene
6. Clostiridium tetani --> tetanus

130

Some bacteria can form spores at the (phase)

end of stationary phase when nutrients are limited

131

How to kill spores

Must autoclave to potentially kill spores (as in done to surgical equipment by streaming at 121 C for 15 min

132

bacterial spore - chemical composition

1. keratin like - coat
2. dipicolinic acid
3. peptidoglycan
4. DNA

133

Properties of growth media - explain

1. Selective media 2. Indicator (differential) media
The same type of media can posses both or neither of these properties

134

Selective media - function

Favors the growth of particular organism while preventing growth of other organism

135

Indicator (differential) media

yields a color change in responde to the medatbolsum of certain organism