Infection 1

Question 1

What are the 3 modes of horizontal transmission?

Answer 1

Contact
Inhalation
Ingestion

Question 2

What is a vector?

Answer 2

An intermediate in the transmission of a micro- organism

Question 3

What is an example of vertical transmission?

Answer 3

Mother to child during child birth or during pregnancy

Question 4

Describe the journey of transmission (5 steps)

Answer 4

Exposure 
Adherence 
Invasion 
Multiplication 
Dissemination

Question 5

What happens once the microorganism enters the body system?

Answer 5

Exotoxins are released (chemicals)

And endotoxins are recognized by the body

Question 6

Name some exotoxins

Answer 6

• cytolytic
• AB toxins
• Superantigens
• enzymes

Question 7

What questions would you ask a patient with a suspected infection?

Answer 7

Symptoms - focal/systemic, severity, duration

Question 8

What is infection?

Answer 8

Invasion of host tissues by microorganisms caused by microbial multiplication, toxins and host response.

Question 9

What is an exotoxin?

Answer 9

A chemical released by a microorganism into the local environment

Question 10

What would you be looking for on examination of a patient with an infection?

Answer 10

Organ dysfunction

Question 11

What SUPPORTIVE investigations would you carry out on a patient with a suspected infection?

Answer 11

Full blood count (neutrophils and lymphocytes)
C-reactive protein (CRP) measure of inflammation
Blood chemistry (liver and kidney function)
Imaging (X-ray)

Question 12

What SPECIFIC tests would you carry out on a patient with a suspected infection?

Answer 12

Bacteriology - Specimen types =swabs, fluids and tissues
Microscopy , Culture and Susceptibility - bacterial cells and cerebrospinal fluid.
Antigen detection
Virology - antigen detection, antibody detection

Question 13

What is contained within the MICROBIAL world?

Answer 13

Viruses, bacteria, parasites and fungi

Question 14

How are viruses classified?

Answer 14

Baltimore scale 1-7

Question 15

What is the difference between enveloped and unenveloped in terms of ability to sterilise?

Answer 15

Enveloped are easier to destroy as the envelope can be punctured

Question 16

Out of RNA or DNA viruses which are more likely to mutate?

Answer 16

RNA is less stable so more likely to mutate

Question 17

What are bacteriophages?

Answer 17

Viruses that infect bacteria

Question 18

What are aerobes?

Answer 18

Bacteria that can survive in oxygen

Question 19

What are obligate aerobes?

Answer 19

Bacteria that require oxygen to survive

Question 20

What are anaerobes?

Answer 20

Can survive in the absence of oxygen

Question 21

What is an Obligate anaerobe?

Answer 21

Bacteria that requires oxygen to survive

Question 22

What shape is staphylococcus?

Answer 22

Cluster (like grapes!)

Question 23

What is the shape of streptococcus?

Answer 23

Rod like

Question 24

Coccus= ?
Bacilli = ?
Spiralus = ?

Answer 24

Coccus= ball
Bacilli = rod
Spiralus = spiral

Question 25

State and give examples of the mechanism of bacterial entry into hosts?

Answer 25

Host entry (via polysaccharide capsule)
Adherence to host cells (pilli)
Invasiveness (collagenase)

Question 26

What is clostridium difficile?

Answer 26

• gram-positive bacteria
• anaerobic
• motile

Question 27

What does infection of C.difficile lead to?

Answer 27

Colitis (inflammation of colon) leads to infectious diarrhoea.
C.difficile produces enterotoxin and cytotoxin which cause the diarrhoea.

Question 28

What is the difference between yeast and mold?

Answer 28

Yeast = single cell
Mold = multicellular

Question 29

What happens after inhalation of streptococcus pneumonie?

Answer 29

Inflammatory response
Vasodilation - exudate of fluid
Fever, pain, redness, loss of function
Bacteria are phagocytosed by neutrophils