10 Microbial infection

Question 1

What are viruses?

Answer 1

Obligate parasites

Question 2

Genetic material in viruses?

Answer 2

DNA or RNA

Question 3

How do viruses replicate?

Answer 3

Using host-cell nuclear synthetic machinery

Question 4

How do viruses divide?

Answer 4

By budding out of the cell or by cytolysis

Question 5

What are some routes of infection?

Answer 5

• Faecal-oral
• Airborne
• Insect vectors
• Blood born

Question 6

What type of virus is HIV?

Answer 6

Retrovirus

Question 7

How do retroviruses work?

Answer 7

DNA makes RNA

RNA makes protein

Question 8

What is the enzyme required for RNA genomes?

Answer 8

Reverse transcriptase

Question 9

Why smallpox (variola virus) has been eradicated?

Answer 9

Very effective vaccine

Vaccine can be given easily after symptoms are seen

Question 10

Bacteria internal membrane structure

Answer 10

No internal membranes

Exception: photosynthetic bacteria

Question 11

Are bacteria diploid or haploid?

Answer 11

Haploid

Single copy of a chromosome

Question 12

Bacterial cytoskeleton is…

Answer 12

Poorly defined

Question 13

Bacterial cell wall structure

Answer 13

Contains peptidoglycan

• Determines shape (rod, coccus, spriochaete)
• Basis of stain

Question 14

How do bacteria divide?

Answer 14

Binary fission

Question 15

How are bacteria motile?

Answer 15

Have a flagellum

- Swim away from toxins and towards food sources

Question 16

What is the vaccine target in bacteria?

Answer 16

Capsule

Question 17

What is the antimicrobial target in bacteria?

Answer 17

Cell wall

Question 18

What is Shigella?

Answer 18

An invasive bacterial pathogen

Question 19

How is Shigella transmitted?

Answer 19

Faecal-oral route

Question 20

Shigella mode of action

Answer 20

Phagocytosed into epithelial cells of GI tract

Replicated and spreads to other cells using host actin

Question 21

Shigella symptoms

Answer 21

Bloody stools

Diarrhoea

Question 22

What is a nosocomial infection?

Answer 22

A hospital acquired infection e.g. MRSA

Question 23

Why are new drugs required?

Answer 23

To combat antimicrobial resistance and shorten treatment

Question 24

Pathogenic E. coli…

Answer 24

is always present in gut

Question 25

How does E. coli cause problems?

Answer 25

Can adhere and get into gut cells

Question 26

Mutation rates in different organisms are...

Answer 26

similiar

Question 27

More mutations occur when...

Answer 27

the generation time is short

Question 28

Are fungi prokaryotic or eukaryotic?

Answer 28

Eukaryotic

Question 29

What do fungi occur in?

Answer 29

Yeasts, filaments or both

Question 30

What do fungi cause?

Answer 30

- Allergy (reactions to fungal product) - Mycotoxicoses (ingestion of fungi and their toxic products) - Mycoses (superficial, subcutaneous or systemic invasion and destruction of human tissue)

Question 31

How do yeasts spread?

Answer 31

They bud or divide

Question 32

What are hyphae?

Answer 32

Filaments which have cross walls or septa | Main mode of vegetative growth

Question 33

What are protozoa?

Answer 33

Unicellular eukaryotic organisms | - Parasites

Question 34

How do protozoa replicate?

Answer 34

In host by binary fission or by formation of trophozoites inside a cell (asexual)

Question 35

How is infection acquired?

Answer 35

By ingestion or through a vector

Question 36

Examples of pathogenic protozoa

Answer 36

Malaria and Leishmaniasis

Question 37

How is plasmodium infection acquired?

Answer 37

Through a mosquito vector

Question 38

How does plasmodium replicate?

Answer 38

Formation of trophozoites inside a cell

Question 39

Protection against malaria

Answer 39

Sickle-cell and β-thalassaemia

Question 40

What are helminths?

Answer 40

Metazoa with eukaryotic cells | Multicellular

Question 41

Lifecycle of helminths

Answer 41

Outside of human host

Question 42

Examples of helminths

Answer 42

Roundworms (Ascaris) Tapeworms Flatworms (Flukes)

Question 43

What are the targets for anti-fungal therapy?

Answer 43

- Cell membrane (ergesterol not cholesterol) - DNA synthesis - Cell wall

Question 44

What Gram negative organism causes hospital acquired pneumonia, burn wounds, particularly affects immunocompromised hosts (e.g. chemotherapy, individuals with cystic fibrosis), and survives on abiotic surfaces?

Answer 44

Pseudomonas aeruginosa

Question 45

What is the abbreviation for extended spectrum beta-lactam resistant E. coli?

Answer 45

ESBL

Question 46

What Gram Neagtive organism causes ITU infections, and survives on abiotic surfaces?

Answer 46

?

Question 47

What Gram Positive organism colonises the nasopharynx, causes bloodstream infections, and disseminated spread (e.g. osteomyelitis & infective endocarditis)?

Answer 47

?

Question 48

What Gram Positive organism is a commensal of gastrointestinal tract, but can cause bloodstream and urinary tract infections?

Answer 48

?

Question 49

What Gram Positive organism is a major cause of antibiotic associated diarrhoea and mortality?

Answer 49

Clostridium difficile