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Flashcards in Microbiology Deck (139):
1

Define nucleocapsid

The capsid most closely associated with the viral nucleic acid.

Nucleic acid + capsid

2

What is the size of a virus?

0.02 - 0.04 um

=  20 - 40 nm

3

Define virion

The virus particle

4

What does a high lymphocyte count indicate?

Viral infection

5

Define the viral envelope

Lipid membrane surrounding either the capsid or nucleocapsid that is formed by the host cells' membrane (not present in all viruses)

6

What do naked viruses lack?

An envelope

7

Define capsid

The protective protein coat shell around the viral genome and forming the core of the virus particle

8

What are the 2 main differences between the gram positive and the gram negative bacterial cell wall?

Gram negative bacteria have a smaller/thinner peptidoglycan layer and they have an additional outer/superficial plasma membrane.  

9

What type of bacteria is this?

Q image thumb

Spirochete

10

What is the funciton of the bacterial flagella?

Locomotion

11

What type of bacteria is this?

Q image thumb

Diplococci

12

What are the 3 main components of the bacterial peptidoglycan cell wall?

 N-acetyl-glucosamine, N-acetyl-muramic acid and a short peptide chain

13

What shape is a bacillus bacteria? 

Rod

14

What are 3 functions of the bacterial capsule?

increases virulence

protects against phagocytosis

prevents dehydration..  

15

What type of bacteria is this?

Q image thumb

Streptococci

16

What is the size of a bacterium?

1-2 um

17

What type of bacteria is this?

Q image thumb

Diplobacillus

18

What type of bacteria is this?

Q image thumb

Streptobacilli

19

What shape is a coccus bacteria? 

Spherical

20

In the peptidoglycan wall of the bacterium, how are the peptide chains connected?

Pentapeptide bridges

21

What are the 3 most common sites of microbe entry? 

The GI tract, skin and respiratory tracts

22

Define cellulitis

An infection of the deep layers of the skin and subcutaneous tissues by bacteria

23

An offensive smelling wound suggests what?

Infection by anaerobic bacteria

24

What type of bacteria release endotoxin?

Gram-negative bacteria

25

What does the catalse test assess?

Tests whether microbe can break down hydrogen peroxide: 2H2O2 → 2H2O + O2

26

What does the coagulase test assess?

Tests whether the microbe can clot plasma by converting fibrinogen to fibrin

27

What is CHA medium?

Chocolate horse blood agar: same as HBA but heated to lyse RBCs and release nutrients

28

What type of haemolysis is clear haemolysis?

Beta haemolysis

29

What type of haemolysis is greening haemolysis?

Alpha haemolysis

30

What colour will beta haemolysis create?

Clear

31

What colour will alpha haemolysis create?

Green

32

What is MacConkey agar enriched with?

Bile salts

33

Bright pink appearance on a MAC plate indicates what?

Lactose fermenter

34

Pale appearance on a MAC plate indicates what?

Non-lactose fermenter

35

Where do RNA viruses generally replicate?

 in the cytosol

36

When are non-enveloped viruses released from a host cell? 

When the host cell lyses

37

What do we call the period between a virus infecting a cell and the intracellular number of viruses rising?

Eclipse period

38

What must a negative strand viruses bring preformed with it when it infects a cell?

RNA-dependent RNA polymerase

39

What are the 2 ways a virus may penetrate a cell?

1 Fuse with the plasma membrane

2 Use receptor mediated endocytosis

40

What do we call the period between a virus infecting a cell and extracellular viruses appearing?

Latent period

41

What do all viruses need  to replicate?

plus sense RNA

42

What type of infection is it called when a virus infects a cell, but does not harm the cell and only emerges at a later time as a lytic infeciton

Latent infection (eg herpesvirus)

43

Varicella-zoster, Epstein-Barr and cytomegalovirus are all examples of what 'family' of viruses?

Herpesvirus 

44

What is the most important/common route of entry for viruses intot he human body?

Respiratory system

45

What type of symetry does the capsid of all non-enveloped viruses have? 

An icosahedral structure.  

46

What type of infection is it where a virus infects a cell and slowly releases virus particles without killing the host cell?

Chronic infection

47

What do virus-infected cells release to prevent neighbours from replicating thus protecting them from infection?

Interferons

48

Where are structural virus-encoded proteins translated?

Ribosomes in the cytoplasm of the host cell

49

Which protein does a virus needs to replicate, which humans don't have?

RNA-dependent RNA polymerase

50

Name 2 ways an enveloped virus can leave the host cell

1 Budding off from cell plasma membrane

2 Golgi-formed vesicles are exocytosed

51

Where do DNA viruses generally replicate? 

In the nucleus

52

Which helminth can grow up to 30-40 cm?

Ascaris lumbricoides

53

What symptoms do scabies cause?

Intense itchiness and dermatitis

54

What is the only helminth that can complete its life cycle in a human host?

Strongyloides

55

What is a roundworm known as?

Nematode

56

Where may Giardia lamblia live in humans?

Duodenum

57

What are helminths known as?

Worms

58

Which organ does entamoeba histolytica typically invade?

Colon

59

Name two helminths that can infect humans directly though the skin

Schistosoma mansoni

Strongyoides stercoralis 

60

What is the pathogen in head lice?

Pediculis capitis

61

What is the pathogen in scabies?

Sarcoptes scabiei

62

What is the pathogen in pubic lice?

Phthirus pubis

63

Which parts of the body do scabies like to infect?

Fingerwebs, elbows, axillae, genitals

64

Which is the most comon disease-causing amoeba in humans?

Entamoeba histolytica 

65

Host in which development occurs but the parasite does not reach sexual maturity.  How is this descibed?

Intermediate host.  

66

What is a very common non-human host of toxoplasma gondii in Australia?

Cats

67

What is enterobius vermicularis better known as?

Pin worm

68

Whihc tick is the pathogenic agent in rapid ascending paralysis?

Ixodes holocyclus

69

What is lice infection generically known as?

Pediculosis

70

Name two type of adhesins used by bacteria

Fimbriae and intimin

71

How do helminths respire?

Through their skin

72

In which countries are schistosoma mansoni likely to be acquired?

Africa, South America, Carribean

73

How many people in the world are infected with a helminth?

>1 billion

74

What effect does vancomycin have on microbiota?

Vancomycin decreases diversity of microbiota, which may be enduring

75

How does strongyloides stercoralis infect a human?

Through skin

76

How does scabies spread?

Direct skin to skin contact

77

Which helminth causes hydatid cysts?

Echinococcus granulosus

78

What do we call the host in which the parasite reaches sexual maturity?

Definitive host

79

What is the pathogen in body hair lice?

Pediculus humanis

80

How is infection with schistosoma mansonii acquired?

Exposure to infected fresh water

81

Which helminths are known to sit in the gut, consume energy and cause weight loss?

Tapeworms

82

What is a very severe complication of tick infection?

Generalised rapid ascending paralysis

83

Where do ectoparasites live?

On or near dermal surface

84

Which type of helminths cause neurocystercercosis?

Taeniae

85

Define parasite

A plant or animal...

that lives on or in another living organism....

on which it is metabolically dependent  

86

Where do body louse lay their eggs?

Clothing

87

What is the classical pathology caused by taenia solium?

Neurocystercercosis

88

Which two bacteria predominate in the gut microbiota?

Fimicutes and bateroidetes

89

Which generations of cephalosporin are better for gram negative bacteria?

Later generations

90

How long must a mosquito have malaria before it can transmit it to a human?

2 weeks

91

What are 4 disadvantages of killed vaccines?

Weaker immune response

High dose

Need adjuvants

Expensive

92

What is pyocyanin?

Turquoise pus produced by eg pseudomonas aeruginosa

93

What is the significance of Ps. aeruginosa being non-fermenting and non-sporing?

It has low nutritional requirements

94

What is the form of malaria that a mosquito may infect a human with?

Sporozoite

95

What stage of the malaria lifecycle is released from hepatocytes?

Merozoite

96

What is the antibiotic of choice for MRSA?

Vancomycin

97

Which type of malaria causes the majority of severe malaria and death?

Plasmodium falciparum

98

What does nosocomial epidemic mean?

Institutional epidemic (eg hospital, nursing home, school)

99

What type of bacteria is pseudomonas aeruginosa? Gram pos/neg, coccus/rod

Gram negative rod

100

What is the main weapon of the immune system in targeting the blood stage of malaria?

Antibodies

101

With diurnal variation, when is temperature lowest?

Morning

102

What are the clinical features of cerebral malaria?

Impaired consciousness, coma, convulsions and long term neurological sequelae

103

What is the single most important preventative technique for opportunistic infections?

Hand hygiene

104

What is the optimum temperatture for immune, endocrine and phsyiological mechanisms?

39.5 C

105

What is group A strep also known as?

Strep pyogenes

106

What oral temperature defines a fever in the morning?

37.2

107

What is the difference between oral temperature and core body temperature?

Oral less than core temp by 0.5C

108

What oral temperature defines a fever at any time of day?

37.8

109

Malaria is most common in people who are travelling for what reason?

Visiting friends or family

110

How long does malaria incubate in the liver for?

7-10 days

111

What is the difference between axillary temperature and core body temperature?

Axillary temp < core body temp by 1C

112

What does saprophytic mean?

An organism can obtain nutrients from dead organic matter

113

What stage of the malaria lifecycle will infect RBCs?

Merozoite

114

What are the two main types of malaria?

Plasmodium falciparum and plasmodium vivax

115

At what stage of the life cycle is the malaria protozoa when it infects hepatocytes?

Sporozoite

116

Which bacteria will often infect a burn in hospital?

Staph aureus

117

What is a fomite?

An inanimate object capable of carrying microorganisms eg stethoscope

118

If someone presents with an acute fever, what are some warning signs of a more serious underlying illnes?

Rigors, rapid evolution, severe muscle pains, impaired conscious state, vomiting, severe headache, rash, jaundice, hypotension, cyanosis, tachypnoea

119

By what process does pseudomonas aeruginosa turn on/off many genes when in a biofilm?

Quorum sensing

120

What are the symptoms of mild malaria?

Flu like illness with fever, headache and malaise

121

Travelling to what part of the world will give you the highest chance of developing traveller's diarrhoea?

South Asia

122

With diurnal variation, when is temperature highest?

Afternoon

123

Which types of malaria can be transmitted from human to human?

NONE

124

What is the most common mode of disease transmission in a traveller?

Vector borne

125

What are the 3 criteria for pyrexia of unknown origin?

Prlonged illness (2-3 weeks duration)

Fever > 38.3 on several occasions

No Dx after intelligent Ix

126

Where does pseudomonas aeruginosa love to grow?

In moist environments

127

What is the normal oral temperature range?

35.8-37.8

128

What are 3 disadvantages of living vaccines that can cause disease?

Back mutation

Spread

Contamination

129

What symptoms are evident during the liver stage of malaria?

None

130

What is the most common preventable medical condition in travellers?

Influenza

131

Which is closer to core body temperature: oral, axillary or ear?

Ear

132

What is the main weapon of the immune system in targeting the liver stage of malaria

Cytotoxic T cells

133

Which type of malaria is most common in sub-Saharan Africa?

Plasmodium falciparum

134

What are 4 advantages of killed vaccines?

Stable

Contamination unlikely

Can't spread

Safe for immunodeficient

135

Which nucleus of the hypothalamus controls temperature set point?

Pre-optic

136

What are 3 advantages of living vaccines?

Broader immune response

Local immunity

Ease of administration

137

Which type of malaria is most common in central/South America and south east Asia?

Plasmodium vivax

138

Which generations of cephalosporin are better for gram positive bacteria?

Earlier generations (and 4th generation)

139

What is the antibiotic of choice for staph aureus?

Flucloxacillin