Infection Session 1

Question 1

Why do antifungals have a high level of toxicity?

Answer 1

Fungi are eukaryotic cells (so are human cells) so it has hard to target fungus and not host cells

Question 2

How are some individuals naturally immune to viruses?

Answer 2

Lack receptors for specific proteins/glycoproteins present on viral surface

Question 3

What must the nucleic acid of a virus be supplemented by to form virions.

Answer 3

Host cell genes

Question 4

Is the protein coat of all viruses similar?

Answer 4

No, varying degrees of complexity

Question 5

What does the Baltimore classification system use to categorise viruses?

Answer 5

Nucleic acid structure and method of replication

Question 6

Mycoplasma, Chlamydiae, Rickettsiae are all obligate intracellular parasites. What does this mean?

Answer 6

Need a cellular host to survive

Question 7

Give an example of a ssDNA non-enveloped virus.

Answer 7

Parvovirus 19

Question 8

Give an example of a dsDNA non-enveloped virus.

Answer 8

Adenovirus

HPV

Question 9

Give an example of a dsDNA enveloped virus.

Answer 9

Herpes virus

Hepatitis B

Question 10

Give an example of ssRNA +ve strand non-enveloped virus.

Answer 10

Coxsackie virus
Norovirus
Hep A&E

Question 11

Give an example of ssRNA +ve strand enveloped virus.

Answer 11

HIV

Hep C

Question 12

Give an example of a disease caused by a ssRNA -ve strand enveloped virus.

Answer 12

Ebola
Lassa Fever
Measles

Question 13

Give and example of a dsRNA non-enveloped virus.

Answer 13

Rotavirus

Question 14

What are bacteriophages?

Answer 14

Viruses that transmit DNA to a bacteria

Question 15

How do bacteriophages cause disease?

Answer 15

Transmitted DNA codes for the production of toxins

Question 16

How can bacteriophages contribute to antibiotic resistance?

Answer 16

Transmit DNA which contains resistance genes

Question 17

Which part of the bacterial structure forms the basis for immunisations?

Answer 17

Polysaccharide capsule

Question 18

What can bacteria release to aid pathogenesis?

Answer 18

Enzymes to increase invasiveness

Chemicals to gain nutrition from surrounding e.g. Iron

Question 19

Which virulence factor do pili affect?

Answer 19

Adherence to host cells

Question 20

How can obligate anaerobes survive in oxygen?

Answer 20

Form spores which coat the bacteria and protect it from oxygen

Question 21

Why can’t the same conditions used to kill vegetative bacteria be used for sterilisation?

Answer 21

Need much higher temperature and pressure to destroy spores

Question 22

What system is used to name bacteria, fungi and parasites?

Answer 22

Linnaean

Question 23

Give two examples of G+ve cocci.

Answer 23

Staph aureus
Coagulase -ve staphylococcus
Alpha- and beta-haemolytic streptococci
Strep pyogenes/pneumoniae
Enterococcus faecalis

Question 24

Give two examples of G-ve cocci.

Answer 24

Neisseria meningitidis/gonorrhoea
Moraxella catarrhalis
Acinetobacter baumannii

Question 25

Give two examples of G+ve bacilli.

Answer 25

Listeria monocytogenes | Bacillus anthracis/cereus

Question 26

Give two examples of G-ve bacilli.

Answer 26

E. coli Salmonella typhi Klebsiella pneumoniae Haemophilus influenzae

Question 27

What is the causative agent in thrush?

Answer 27

Candida albicans

Question 28

Which organism causes an AIDS defining meningitis?

Answer 28

Cryptococcus neoformans

Question 29

What type of mould are ringworm and athlete's foot?

Answer 29

Dermatophytes

Question 30

What are single-celled parasites called?

Answer 30

Protozoa

Question 31

Give two examples of protozoa.

Answer 31

Giardia lamblia Cryptosporidium parvum Plasmodium falciparum

Question 32

What category of pathogen do roundworms, tapeworms and flukes belong to?

Answer 32

Helminths

Question 33

Give an example of a fluke which can cause malignancy.

Answer 33

Schistosoma mansoni

Question 34

What S/S are associated with tapeworm infection?

Answer 34

None - usually asymptomatic but can cause neurological disease

Question 35

What is the difference between yeasts and mould?

Answer 35

Yeasts are single celled fungi | Moulds are multicellular fungi

Question 36

What is an infection?

Answer 36

Invasion of a host's tissues by microorganisms and disease

Question 37

What are microbiota?

Answer 37

Microorganisms carried on skin and mucosal surfaces which are normally harmless or even beneficial

Question 38

What are the three methods of horizontal transmission?

Answer 38

Contact Inhalation Ingestion

Question 39

Why dint droplets spread as far as aerosols?

Answer 39

They are heavier

Question 40

What are the stages that allow microorganisms to cause disease?

Answer 40

Exposure --> adherence --> invasion --> multiplication --> dissemination

Question 41

Why is targeting the host immune response in treatment of infection potentially more effective than killing the pathogen itself?

Answer 41

Host immune response is usually more destructive

Question 42

What are exotoxins?

Answer 42

Molecules released by a pathogen which can damage the surroundings to promote survival of the pathogen

Question 43

What are endotoxins?

Answer 43

Parts of the bacterial cell wall which are released when the bacteria dies

Question 44

What is the difference in supportive and specific investigations when identifying an infection?

Answer 44

Supportive identify to what extent a pt is unwell | Specific identify the causative agent

Question 45

What supportive investigations can be performed in suspected infection?

Answer 45

``` FBC CRP LFTs U&Es Imaging Histopathology ```

Question 46

What is MC&S in specific investigations of infection?

Answer 46

Microscopy, Culture and antibiotic Susceptibility

Question 47

Which specific investigations in infection can utilise dead pathogens e.g. in heart valve removal?

Answer 47

Antigen and nucleic acid detection

Question 48

What virology specific investigations can be performed in a suspected infection?

Answer 48

Antigen detection Antibody detection Detection of viral nucleic acid