8. Infections On Surfaces

Question 1

What is a surface?

Answer 1

Interface between a solid and either a liquid or gas

Question 2

What bacteria is most present in the vagina? Why is that?

Answer 2

Lactobacillus - keeps pH low and Candida at bay

Question 3

Give 2 examples of natural external surface infections, and 2 internal

Answer 3

External - gastroenteritis, UTI, pneumonia

Internal - endocarditis, empyema, osteomyelitis

Question 4

Give 3 examples of prosthetic surfaces which can become infected

Answer 4

Prosthetic joints
Prosthetic heart valves
Intravascular lines
Peritoneal dialysis catheters

Question 5

What bacteria can cause infections in all 3 of prosthetic valve endocarditis, prosthetic joint infections and cardiac pacing wire endocarditis?

Answer 5

Staphylococcus aureus

Question 6

How do pathogens adhere to the surface at the site of infection (host cells or prosthetic surface)?

Answer 6

Via pili or fimbriae

Question 7

What is a biofilm?

Answer 7

Extracellular polymers and matrix that change the genotype of the bacteria to a more sessile form. These produce more slime and this protects the bacteria against the host defences

Question 8

What are the two main challenges with treating an infection caused by bacteria that makes biofilm?

Answer 8

Poor antibacterial penetration into biofilm

Low metabolic activity of biofilm micro-organisms

Question 9

Give 3 ways to prevent natural surface infections

Answer 9

Maintain surface integrity
Prevent bacterial surface colonisation
Remove colonising bacteria

Question 10

Give 3 ways to prevent infection on prosthetic surfaces

Answer 10

Prevent contamination
Inhibit surface colonisation
Remove colonising bacteria