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Microbiology Flashcards

1
Q

How is the prokaryote chromosome like?

A

Single, super-coiled, double stranded closed circular

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2
Q

Which eukaryote has cell wall? What is it known as?

A

Fungi

Sterols

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3
Q

How do prokaryotes divide?

Which organism is particularly slow to grow?

A

Binary fission.

TB.

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4
Q 
What is the role of gyrases?
Which antibiotic class target this?
A

Relieves unwinding stress.

Quinolones.

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5
Q

Does nucleoid have a nuclear membrane?

A

No

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6
Q

What 2 compounds are found in the peptidoglycan as repeated polysaccharide structure?

A

NAM and NAG

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7
Q

Which antibiotic class target the cell wall?

Are they bacteriostatic or bactericidal?

A

B-lactams (Penicillin, Cephalosporins) and Glycopeptide

Bactericidal

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8
Q

What is the cell wall like in gram-positive organisms?

A

THICK MULTI-layered peptidoglycan with glycolipids

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9
Q

What is the cell wall like in gram-negative organisms?

A

LPS at the outermost surface followed by outer membrane then thin peptidoglycan layer followed by inner membrane

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10
Q

Which layer of cell wall is responsible for endotoxin?

This is found in gram-___?

A

LPS - antigenicity, pro-inflammatory.

Gram Negative.

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11
Q

What charge does LPS give the cell membrane?

A

Negative due to phosphate groups

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12
Q

What are the 3 arrangements of proteinaceous extensions?

A

Monotrichous, Lophotrichous, Peritrichous

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13
Q

Rotary movement of flagella is?

Is the flagella antigenic?

A

H+ dependent.

Yes.

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14
Q

What is the fimbriae/ pilli involved in? (3)

A

Surface attachment/ biofilm formation
Horizontal DNA transfer
Mobility (not for gram-neg)

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15
Q

What is the sequence to identify the 16s rRNA in mRNA?

A

Shine Dalgarno sequence

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16
Q

Is the prokaryotic mRNA polyadenylated?

A

No

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17
Q

Since there is no golgi apparatus in prokaryotes, which organelle processes proteins?

A

Cytoplasmic membrane

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18
Q

How do transcription and translation occur in prokaryotes?

A

Simultaneously

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19
Q

What kind of prokaryotes grow best at 37 deg?

A

Mesophiles

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20
Q

What pH range and osmolarity is ideal for human commensals?

A

pH6.8-7.2.

0.85% NaCl

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21
Q

Does heterotrophs or autotrophs require carbon source to be provided?

A

Heterotrophs

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22
Q

What respiratory method does facultative anaerobes use?

A

Preferentially uses O2 as terminal electron acceptor but able to switch

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23
Q

What respiratory method does aerotolerant anaerobes use?

A

Anaerobic metabolism.

Just able to tolerate O2

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24
Q

What is the difference between obligate anaerobes and capnophillic organisms in the presence of O2?

A

Obligate anaerobes are killed in O2

Capnophiles not necessarily

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25
Q

Are obligate anaerobes or aerobes able to generate more ATP?

A

Obligate aerobes as O2 has higher reductive potential than nitrates/ sulfates

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26
Q

What are the 4 phases of growth in prokaryotes?

A

Lag
Exponential/Log
Stationary/ Plateau
Death/Decline

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27
Q

What are chains, clusters, rod, curved rod morphologies called?

A

Chains - cocci
Clusters - coccus
Rod - bacillus
Curved rod - Vibrio

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28
Q

What is the difference between a Spirillum and Spirochaete?

A

Spirillum - rigid spiral bacterium

Spirochaete - flexible spiral bacterium

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29
Q

How does spiral bacteria move?

What kind of solution can they move better in?

A

Cock-screw movement.

Viscous solution such as saliva and semen

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30
Q

How does fusiform bacteria look like?

A

Elongated and slender with tapered ends

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31
Q

What is the 2nd most common cause of sore throat?

A

Fusiform

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32
Q

What characteristics does a capsule provide a bacteria with? (3)
1 example of a bacterium with capsule

A

Phagocytosis protection, Virulent, Part of biofilm

Klebsiella pneumoniae.

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33
Q

What are spores? When do they form?
What is term for when a spore becomes active again?
1 example of a bacterium that produces spore.

A

Inert structures resistant to physical and chemical challenge.
Forms when cells cannot grow due to stressors.
Germination.

C. Difficile

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34
Q

It is the retention of which solution (2) in what structure that gives gram positive its colour?
What colour is it?

A

Crystal violet, Iodine (mordant)
In thick peptidoglycan.

Purple.

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35
Q

What colour do gram-negatives stain? What is it stained by? (2)

A

Pink.

Safranin Pink or Basic Fuchsin (Counter-stain)

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36
Q

What is used as the decolouriser in gram-staining?

A

Ethanol

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37
Q 
Which organisms (2) shows gram-variability? Due to??
What stain should be used then?
A

M. tuberculosis due to waxy, lipid-rich cell wall thus stain not taken up well.
Use Acid-fast (Ziehl Neelson) stain

Spirochaete as it is too thin to take up crystal violet.
Use silver impregnation.

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38
Q

What component in the mannitol salt agar preferentially selects for what kind of bacteria?

A

7.5% salt.

For Staphylococci.

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39
Q

Salmonella-Shigella agar contains what to inhibit what organisms?

A

Contains bile salts to inhibit coliforms

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40
Q

What is the difference between a selective and differential media?

A

Selective - select/ permit growth of 1 organism over another

Differential - producing visible changes in colonies for identification

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41
Q

What does MacConkey agar help to identify? What is the colour?
What are the 2 inhibitors in it and what does it inhibit?

A

Enterobacteriaceae - turns neutral red to pink from fermenting lactose.

Contains bile salts and crystal violet to inhibit gram negative enteric bacilli.

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42
Q

What does eosin-methylene blue media inhibits?

What does it differentiate and how?

A

Inhibits gram positives.

Lactose fermenters: Produce acid and absorbs dye -> Purple black (Or metallic green sheen for E.Coli)

Non-lactose fermenters: Protein deamination -> increase pH -> dye not absorbed -> colourless

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43
Q

What colour does E.Coli produce in the eosin-methylene blue media?

A

Metallic green sheen

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44
Q

What bacteria is blood agar specifically used to identify? On the basis of what?

A

Streptococcus spp.

Via haemolysis

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45
Q

What are the 3 types of haemolysis on a blood agar and what are their colours?

A

a (incomplete) - greenish discolouration around colonies (Hb oxidation to MetHb by H2O2)
B (complete) - Yellow and complete clearing around colonies due to streptolysin
y - no change, no haemolysis

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46
Q

Which lancefield groupings show B-haemolysis and which show y-haemolysis?

A

B: A (S. pyogenes), B, C (Large pyogenic or small colonies), F, G

y: D

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47
Q

What organism produces endotoxin and what produces exotoxins?

A

Endotoxin - Gram neg (from LPS)

Exotoxin - Gram Pos

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48
Q

Which bacteria is coagulase positive?

A

S. Aureus

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49
Q

Which bacteria hydrolyses lipid?

A

Clostridia spp.

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50
Q

What is the difference between polyclonal and monoclonal Ab?

A

Polyclonal - to a specific microbe/ virus

Monoclonal - to specific component

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51
Q

Slide agglutination reactions show that what is present?

What kind of tests are these?

A

Antigens (sample) to a particular anti-sera (from lab).

Serological tests.

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52
Q

What are the 4 stages of PCR?

A

Denaturation of DNA
Annealing of primers to target
Extension via polymerase
Amplification

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53
Q

What kind of rRNA is high conserved (evolves slowly) and varies between strain?
Thus can be ribotyped

A

16S rRNA

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54
Q

What is needed to interpret the mass spectrum result produced from a MALDI-TOF?

A

A reference library to compare

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55
Q

What is microbiome?

A

Study of genetic material of all microbes living on/ inside the human body

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56
Q

What does virulence mean?

A

Capacity of microbe to cause host damage

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57
Q

What are the terms used to describe an endogenous organism with a mutualistic relationship with the host that limits threat from exogenous pathogens?

A

Commensals/ Symbiotic relationship

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58
Q

What are organisms that cause infection when there is a change in natural immunity (E.g. Immunocompromised)?
Are these usually endo or exogenous?

A

Opportunistic pathogens.

Endogenous.

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59
Q

What are organisms growing in culture by accident known as?

A

Contaminant

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60
Q 
What organism (and what kind) causes thrush in the throat/ GU tract or skin?
When does this occur?
A

Candida, a fungi.

Immunocompromised state.

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61
Q

How do yeast (fungi) multiply?

A

Budding

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62
Q

What does the tip of true hyphae contain?

A

Proteases to break surfaces

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63
Q

What is a common mould (fungi) that infects the immunocompromised?

A

Aspergillus spp.

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64
Q

What are organisms causing Malaria, E. histolytica and cryptosporidiosis called?

A

Protozoa

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65
Q

How does Neisseria meningitidis and neisseria gonorrhoeae appear in microscopy?

A

Gram-negative diplococci growing intracellularly

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66
Q

A pink diplococci bacteria that grows intracellularly is seen on microscopy.
What are the 2 possible bacteria?

A

Neisseria meningitidis

Neisseria gonorrhoeae

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67
Q

What are 4 gut commensals (Coliforms)?

A

Most E.Coli
Klebsiella
Enterobacter
Proteus

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68
Q

Salmonella, Shigella and E.Coli O157 (Coliforms) causes pathology where?

A

GI

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69
Q

Coliforms are gram?? Morphology?

A

Gram negative bacilli

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70
Q

What are Gram negative bacilli from the normal bowel flora called?

A

Coliforms

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71
Q

What is the 1st line abx used to treat coliforms?

Route of administration and 1 potential side effect?

A

Gentamin.

IV, Nephrotoxic.

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72
Q

What is the exotoxin superantigen produced by S. Auerus?

A

TSST-1

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73
Q

What could adversely happen when a coliform dies?

A

Endotoxin will be released from the cell wall (LPS) causing inflammation and sepsis

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74
Q

What are the 3 components of the LPS? (From inner to outer)

A

Lipid A, Core, O Antigen

**Can be used for serology typing

75
Q

Where are H antigens found?

A

Flagella

76
Q

3 examples of pyrogenic cytokines?

A

TNF, IL-1, IL-6

77
Q

What may fever cause in young children?

A

Convulsions/ seizures

78
Q

Does direction does sepsis shifts haemostasic balance to?

But what may eventually happen?

A

Coagulation.

Eventually clotting factors consumed –> hemorrhagic risk

79
Q

Example of a Group A Strep (GAS)?

What type of haemolysis does it show?

A

S. pyogenes.

Beta

80
Q

What haemolysis does S. pneumoniae show?

A

Alpha

81
Q

What are 7 diseases that can be caused by S. pyogenes?

A 
Strep throat
Scarlet fever
Cellulitis
Necrotising fasciitis
Puerperal (6 weeks after childbirth) sepsis
Rheumatoid arthritis
Glomerular nephritis
82
Q

What is the coagulase, catalase and oxidase status of S. Aureus?
How much NaCl can it tolerate?

A

Coagulase pos
Catalase pos
Oxidase neg

Tolerates 15% NaCl

83
Q

What kind of infections does S. Aureus commonly cause? (5)

A 
Skin
Soft tissue
Wound
Bone
Joint
84
Q

What kind of S. Aureus can cause food poisoning?

A

Only strains producing enterotoxins

85
Q

How is MRSA usually acquired?

A

Nosocomial

86
Q

Where is S. epidermidis usually found?

Coagulase???

A

Skin, mucous membrane

Coagulase neg

87
Q

Where is S. Aureus usually found?

A

Nose, Perineum

88
Q

How are infections from S. epidermidis acquired? Usually in who (2)?

A

Nosocomial.

Immuncompromised, those with foreign devices

89
Q

Clostridium spp. is gram?

What is the O2 requirement and morphology?

A

Gram positive bacilli

Anaerobic

90
Q

What is the mode of dissemination of clostridium spp.?

A

Spores

91
Q

Where is clostrium spp. found? (2)

A

Normal bowel flora (thus in faeces)

Soil

92
Q

What can clostridium perfringens cause?

A

Gas gangrene (after wound contamination)

93
Q

What can clostridium tetani cause?

A

Tetanus (fatal paralysis)

94
Q

What is Clostridiodes difficile associated with? Usually in who?
What is the hallmark pathology? (2)

A 
Antibiotic treatment (proliferates in altered bowel flora)
Elderly
Severe diarrhoea and pseudomembranous colitis
95
Q

Does bacteraemia always show signs/ symptoms?

A

No.
It just indicates a presence of bacteria in the blood.

Sepsis will show signs/symptoms (Systemic, overwhelming inflammation)

96
Q

Common bacteria causing UTI? (2)

A

E.Coli

Klebsiella

97
Q

What are the 3 pathogenic clostridium spp.?

A

clostridium perfringens
clostridium tetani
clostridiodes difficile

98
Q

What are the 2 a-haemolytic strep?

A

S. pneumoniae (Pneumonia, Meningitis)

S. viridans (Endocarditis)

99
Q

What is Group B Strep associated with?

A

Neonatal meningitis

100
Q

What are the non-haemolytic strep?
What disease can it cause?
Where is it usually found normally?

A

Enterococcus sp.
UTI
Gut commensal

101
Q

What are 2 gram positive aerobic small bacilli?

A 
Corynebacterium sp. (Diptheria)
Listeria monocytogenes (meningitis)
102
Q

What are 2 gram positive aerobic large bacilli?

A 
Bacillus cereus (Food poisoning)
Bacillus anthracis (Anthrax)
103
Q

What are the gram positive and gram negative anaerobic bacilli?

A

Gram pos: Clostridium sp.

Gram neg: Bacteroides sp.

104
Q

What are the 2 gram negative microaerophilic bacilli?

A

Small curved - campylobacter sp.

Spiral - Helicobacter sp.

105
Q

What are the 2 gram negative aerobic bacilli?

Strict (2), Small (2), Large (1)

A
  • Strict -
    Legionella sp
    Pseudomonas aeruginosa

-Small-
Bordetella pertussis (Whooping coigh)
H. influenzae (COPD exacerbation)

-Large-
Coliforms

106
Q

What is bacteriostatic and bactericidal?

A

Bacteriostatic - inhibits growth of bacteria

Bactericidal - kills

107
Q

When the most of a drug does not bind to plasma protein (unbound/free), how does it influence Vd, Cl and T1/2?

A

Slower Cl

Higher Vd and T1/2

108
Q

How are Abx usually excreted?

A

Urine (Renal)

Faeces (Hepatobiliary)

109
Q

What is flucloxacillin used for?

A

Staph and strep skin infection

**NOT FOR MRSA!

110
Q

What is the mode of excretion of penicillin and is it safe to use in pregnancy?

A

Renal (rapid).

Safe.

111
Q

What is the side effect of penicllin?

A

Hypersensitivity/ allergic/ rash (cross-reactivity with across all penicillins and sometimes 5-10% cephalosporins)

112
Q

What is an example of a 3rd generation cephalosporin?

A

Ceftriaxone

113
Q

What does B-lactam target?

A

Irreversibly binds to Penicllin-binding protein.
Resembles D-alanine D-alanine which is used for peptidoglycan cross-linking –> not processed –> halts cell wall synthesis –> cell lysis

114
Q

What is the other component of Augmentin other than Amoxicillin? What is it used for?

A

Clavulanic acid.

B-lactamase inhibitor.

115
Q

What are 2 examples of 1st gen cephalosporins?

What are they used for?

A

Cefazolin, Cefalexin.

For Strep and Staph

116
Q

What is an example of a carbapenem?
What is it used for?
What is it resistant to?

A

Meropenem (Last resort for Gram neg)
Hospital level infectious disease.
Resistant to B-lactamase.

117
Q

What are the 3 natural pencillins? What are their route of administration?

A

Benzylpenicillin/ Penicillin V - Oral
Phenoxymethylpenicillin/ Penicillin G - IV
Benzathine penicillin (Long-acting) - IM

118
Q

What does Augmentin NOT cover?

A

MRSA and P. aeruginosa

119
Q

How well is flucloxacillin absorbed in the GIT?

A

Not absorbed well

120
Q

What is Tazocin made of?
Route of administration?
What does it not cover?

A

Piperacillin (extended spectrum against Gram Neg such as Pseudomonas) + Tazobactam (B-lactamase inhibitor).

IV.

MRSA.

121
Q

What does Temocillin cover?

Route of administration?

A 
Gram neg (coliforms), ESBL-producing organisms
IV.
122
Q

What is the mode of excretion of cephalosporins? Is it safe for pregnancy?

A

Urinary.

Safe.

123
Q

Are pencillins or cephalosporins more resistant to B-lactamases?

A

Cephalosporins

124
Q

What happens as the cephalosporin generations progress?

A

Spectrum extends

**Also increases risk of C. diff infection

125
Q

What does Vancomycin/ Teicoplanin target? (4)

A

Binds to end peptide chain (D-alanine D-alaine) of NAM and NAG of Peptidoglycan –> prevents further peptidoglycan synthesis
Blocks PBP from accessing substrate
Interfere with membrane and peptidoglycan precursor molecule
Reduces cross-linking and activity of lytic enzyme s–> weaken cell wall

126
Q

What does glycopeptide cover and not cover?

A

Only covers Gram pos.

No activity against Gram neg (cannot reach peptidoglycan due to outer membrane)

127
Q

What happens to patients with kidney failure who are taking vancomycin?

A

Toxic blood accumulation thus further nephrotoxicity.

**Renal excretion

128
Q

Are most antibiotics that inhibit protein synthesis bacteriostatic or bactericidal?
What is the exception?

A

Most are bacteriostatic (Reversible; protein synthesis resumes when Abx removed)

Aminoglycosides irreversibly bind to 30S ribosome –> bactericidal

129
Q

Why must Aminoglycosides be given IV (or IM)?

A

Not absorbed from gut

130
Q

What does aminoglycosides cover?
1 common example of an aminoglycoside?
Route of excretion?
Side effects? (2) How are these prevented?

A

Gram neg aerobic organisms
Gentamicin
Renal
Nephrotoxic and neurotoxic (to CN VIII - deafness, dizziness) –> monitor blood levels

131
Q

What is the spectrum of tetracycline?
What is it useful against? (2)
What are the side effects (2)
Who should it not be given to? (3)

A

Broad.
Intracellular and atypical organisms (C. trachomatis)
Increased secondary infections, stain and impair structure of bones and teeth
Infants, children, pregnant women

132
Q

What doxycycline be used to treat?

A

Lyme’s disease due to its mild anti-inflammatory effect

133
Q

What are macrolides used for (2)?
Route of excretion?
Polarity?

A

Intracellular pathogens and if there is penicillin allergy
Hepatic
Lipophillic (diffuses easily into cell)

134
Q

Is erythromycin safe for pregnancy?

A

Yes

135
Q

What are the Abx that binds to 30S ribosomal subunit?

A

Aminoglycosides

Tetracycline

136
Q

What are the Abx that binds to 50S ribosomal subunit?

What do they interfere with?

A

Macrolides
Clindamycin (Lincosamides)
Chloramphenicol
Linezolid

Translocation/ peptide bond formation

137
Q

What is fusidic acid usually used for?

What does it block?

A

Superficial Staph skin infection (Topical)

Complexes with Elongation Factor-G to block peptide chain elongation

138
Q 
Is Metronidazole (Flagyl) bacteriostatic or bactericidal?
What does it cover?
How is the Abx activated?
Side effects (3)?
A

Bactericidal
Anaerobes, parasites/protozoa
Partial reduction in cytosol –> toxic intermediate formation –> DNA strand breakage
Disulfiram-like reaction with Alcohol, metallic taste, furred (white coat) tongue

**Disulfiram is used to treat alcoholism - produces hangover like symptoms

139
Q 
Are fluoroquinolones (Levofloxacin, Ciprofloxacin) bacteriostatic or bactericidal?
What does it cover?
Mode of excretion?
Side effects (1)?
A

Bactericidal
Gram neg and some gram pos
Renal
C. difficile infection

140
Q

What is the mode of action of quinolones (Nalidixic acid)?

A

Binds to DNA gyrase (Topoisomerase) -> prevents super-coiling -> indirectly inhibits DNA synthesis

141
Q

What do Trimethoprim and sulfonamides inhibit?

Is the result bacteriostatic or bactericidal?

A

Folic acid synthesis

Bacteriostatic

142
Q

What is the mode of action of sulfonamides?

A

Act as PABA analogues to competitively inhibit Dihydropteroate synthase

143
Q 
What does Trimethoprim inhibit? Why does it work better in bacteria?
What does it cover?
Mode of excretion?
1 disease it is commonly used to treat
Often combined with?
A 
Inhibits dihydrofolate reductase.
Much higher affinity in bacteria.
Some gram neg, some gram pos.
Renal.
Acute UTI.
With Sulfamethoxazole --> Co-trimoxazole (Septrin).
144
Q

What is folic acid used to synthesize? (4)

A

Thymidine, Purines, Methionine, Glycine

145
Q

What is a side effect of Ciprofloxacin?

A

Tendinitis

146
Q

As all Abx disrupts gut flora, can they affect the absorption of oral contraceptives?

A

Yes

147
Q

Why are Abx sometimes given in combination (3)?

A 
Prevent resistance (E.g. for TB)
Synergistic effect
Cover a broader range of organisms
148
Q

Why should bacteriostatic and bactericidal Abx be used together?

A

NEVER COMBINE THESE 2 ABX TOGETHER!

Difficult to kill abx as metabolism of bacteria is slowed by static effects.

149
Q

What are the 4 Cs that increases the risk of C. Difficile infection?

A

Cephalosporin
Ciprofloxacin
Co-amoxiclav
Clindamycin

150
Q

Can vancomycin be used against Lactobacillus?

A

No, it uses D-alanine D-LACTATE as side chain in cell wall

151
Q

Why won’t pencillin work against mycoplasma?

A

No cell wall

152
Q

Why is vancomycin not effective against gram neg?

A

Outer membrane prevents entry

153
Q

What condition is required for metronidazole to be taken up and activated?

A

Anaerobic condition

154
Q

What are organisms that survive Abx tx known as?

How is its metabolism like?

A

Persistor cells (Not resistant but tolerant to treatment) - grow again when tx discontinued.

Inert and slow-growing (thus not killed)

155
Q

What can grow on catheters that is resistant to damage by Abx and host immunity?

A

Biofilms

156
Q

High antibiotic use is associated with?

A

Abx resistance

157
Q

What are the 2 types of genetic variation that may contribute to abx resistance?

A
  1. Mutation (rapid growth -> mutation -> new variants)
  2. Horizontal gene transfer
    - Transformation (uptake foreign genetic material from environment)
    - Transduction (bacteriophage)
    - Conjugation (plasmid, pili)
158
Q

What are 4 mechanisms in which abx resistance can be acquired?

A
  1. Altered permeability (Altered influx, Active efflux)
  2. Inactivating enzymes (E.g. ESBL)
  3. Replacement of sensitive pathway (E.g. resistant enzyme in folic acid pathway)
  4. Altered target site (E.g. Staph PBP2a, Altered DNA gyrase)
159
Q

Amino acid change in which 30S subunit will prevent Streptomycin from binding?

A

S12

160
Q

Methylation of which 50S subunit will prevent erythromycin from binding?

A

25S

161
Q

ESBL-producing organisms are resistant to which penicillins and which generation of cephalosporins?
Which 2 Abx can overcome this?

A

All penicillins including monobactam and to 3rd gen cephalosporins.

Cephamycin, Carbapenems

162
Q

What is carbapenemase resistant to?

A

All penicillins, cephalosporins, carbapenems

163
Q

What does colistin target?
Side effects?
When is it used?

A

Polymyxin Abx that targets outer membrane of Gram neg
Nephrotoxic if given through injection
Last resort for NDM-1 resistant bacteria (Metalloenzyme/ carbapenemase)

164
Q

Why is it important to get rid of uncommon but resistant pathogens?

A

Can transfer plasmid to a more virulent strain

165
Q

What is sub-therapeutic doses of Abx associated with?

A

Resistance, selects and allows for sub-resistant population of bacteria to grow

166
Q

What virus has an icosahedral (20 faces) symmetry?

A

Adenovirus

167
Q

What are the 7 steps of viral infection?

A 
Attachment
Binding to specific receptor
Entry
Un-coating
Nucleic acid and protein synthesis
Assembly 
Release
168
Q

How do enveloped and non-enveloped virus enter host cells?

A

Enveloped - fusion of lipid membrane via viral enzyme -> capsid injected inside
Non-enveloped - endocytosis

169
Q

What is being used in viral nucleic acid and protein synthesis?

A

Viral enzymes (E.g. Proteases, RNA dependent RNA polymerase) and ALWAYS host ribosomes

170
Q

How are enveloped and non-enveloped virus released from host cell?

A

Budding - human cell membrane fuses to make up the envelope when budding off
Cell lysis - non-enveloped

171
Q

What are 3 possible reasons for cell death to occur in a viral infection?

A

Lysis
Hijacking of cell machinery
Immune system

172
Q

What cancer is Human Herpes Virus Type 8 associated with?

A

Kaposi’s sarcoma

173
Q

Can a virus spread even if a person is asymptomatic?

A

Yes

174
Q

What are the 4 possible reasons for a positive detection of the virus but without any presenting symptoms?

A
  1. Convalescent (resolving)
  2. Late stage of incubation
  3. Reactivation
  4. Asymptomatic
175
Q

Where can Torque Teno Virus be found?

A

In >90% adults worldwide but not associated with human pathogenicity

176
Q

What study can be done to establish if a virus is a pathogen?

A

Case-control study

177
Q

What are 3 components of the immune system against viral infection?

A
  1. Cytotoxic T cells - detects non-human Ag on infected cells and induce apoptosis
  2. Neutralising Ab (IgG, IgM) - stops infection/ re-infection
  3. Innate immunity involving inducing IFN and TLR3 by viral DNA
178
Q

What is the difference between NOTIFIABLE diseases, organisms and health-risk states?

A

Diseases - reported if suspected/ confirmed
Organisms - may not always cause notifiable disease (E.g. Chicken pox disease is not notifiable but the virus VZV is notifiable)
Heath risk states - Syndromes caused by serious, transmissible organisms (yet to be identified)

179
Q

What does it mean when a virus has become quiescent? (5)

2 examples of such virus.

A

Not actively replicating, dormant/ latent, asymptomatic, not infectious, can reactivate.

HSV, VZV

180
Q

HIV and Hep C can result in chronic infection for many years. How might this present?

A

Can be asymptomatic but still infectious for many years before life-threatening complications occur

181
Q

How can viruses be detected in the lab? (2)

A
  1. Ab response (Past vs current infection)

2. Virus itself - PCR, Ag detection, //Obsolete// (cell culture, electron microscopy)

182
Q

What can IgM and IgG titres of viral Ab suggest?

A

IgM - recent/ acute

IgG - chronic/ late/ past infection

183
Q

When are paired blood samples for viral titre of IgG taken?

What difference should you expect?

A

During acute and convalescent phase.

IgG titres should have increased

Principles (14 decks)

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