Session 6 Lecture 2

Question 1

What is a surface?

Answer 1

Interference between a solid and either a liquid or gas

Question 2

Give some examples of viruses that affect the skin?

Answer 2

Papilloma - warts and verucas

Herpes simplex - cold sores

Question 3

Give some examples of gram positive bacteria that affect the skin?

Answer 3

Staph aureus, coagulase negative staphylococcus aureus and corynebacterium

Question 4

Give some examples of gran negative bacteria that affect the skin

Answer 4

Enterobacteriaceae

Question 5

Give some examples of fungi that affect the skin

Answer 5

Yeasts - candida

Dermatophytes - athletes foot

Question 6

Give some examples of parasites that affect the skin

Answer 6

Mites - eg public lice

Question 7

How do people get infections?

Answer 7

Invasion, migration, innoculation or haemotogenous

Question 8

Give am example of an infection that acts by invasion?

Answer 8

Strep pyogenes pharyngitis

Question 9

Give an example of an infection that is acquired by migration?

Answer 9

Escherichia coli urinary tract infection

Question 10

Give an example of an infection acquired by innoculation

Answer 10

Coagulate negative - staphylococcus prosthetic joint infection

Question 11

Give an example of an infection that is spread haemotogenously?

Answer 11

Viridans strep endocarditis

Question 12

What is the biggest complication of prosthetic point surgery?

Answer 12

Infection

Question 13

Give an example of an external natural surface infection

Answer 13

Cellulitis, pharyngitis, conjunctivitis, GI, UTI and pneumonia

Question 14

Give examples of internal natural surface infections

Answer 14

Endovascular - endocarditis and vasculitis
Septic arthritis
Osteomyelitis
Empyema

Question 15

What is septic arthritis

Answer 15

Inflammation of a joint caused by bacterial infection.

Question 16

What is osteomyelitis?

Answer 16

Bone infection caused by bacteria. Occurs when you have a broken bone without breaking the skin therefore bleeding internally

Question 17

What is empyema?

Answer 17

Condition where pus builds up in the pleural space, often as a complication of pneumonia

Question 18

Give examples of prosthetic surface infections

Answer 18

Intravascular line, peritoneal dialysis catheters, prosthetic joints, cardiac valves, pacing wires, endovascular grafts

Question 19

What is hydrocephalus?

Answer 19

Build up fluid on the brain. The excess fluid puts pressure on the brain which can damage it.

Question 20

What bacteria is responsible for causing prosthetic valve endocarditis <1year post op?

Answer 20

Coagulase negative staphylococci

Question 21

What bacteria are responsible for prosthetic valve endocarditis >1year post op?

Answer 21

Viridans streptoccci, enterococcus faecalis, staph aureus, HACEK group, Candida

Question 22

What are the causes of prosthetic joint infections?

Answer 22

Coagulase negative staphylococci and staphylococcus aureus

Question 23

What are the processes in pathogenesis of infection at a surface?

Answer 23

• Adherence to host cells or prosthetic surfaces
• Biofilm formation
• Invasion and multiplication
• Host response

Question 24

Define pyogenic?

Answer 24

Pus forming

Question 25

What is adherence?

Answer 25

The bacteria sticking to host cell membrane

Question 26

What is a biofilm?

Answer 26

Any group of microorganism stick to eachother and adhere to the surface.

Question 27

What is quorum sensing?

Answer 27

This allows both gram positive and negative bacteria to sense one another and regulate many physiological activities

Question 28

What does quorum sensing control?

Answer 28

Sport Latino, biofilm formation and virulence factor secretion

Question 29

What are autoinducers?

Answer 29

These are signalling molecules that are expressed in response to changes in population density of the cell.

Question 30

What happens to the autoinducers concentration when the density of quorum sensing bacteria increase?

Answer 30

Autoinducer concentration increases

Question 31

What is the aim of infection management?

Answer 31

Sterilise tissues and reduce bioburden

Question 32

What are the challenges facing the management of infection?

Answer 32

- Poor antimicrobial penetration into biofilm - Low metabolic activity of biofilm microorganisms - Dangers/difficulties of surgery

Question 33

Why does the low metabolic activity of biofilm microorganisms affect the activity of an antimicrobial?

Answer 33

Antimicrobials work best when the bacteria are actively multiplying

Question 34

How do you prevent a natural surface from infection?

Answer 34

Maintain surface integrity, prevent bacterial surface colonisation and remove colonising bacteria

Question 35

How do you prevent infections on prosthetic surfaces?

Answer 35

- Prevent contamination - Inhibit surface colonisation - Remove colonising bacteria