Skin ecology and indwelling devices

Question 1

What is secreted from the sebaceous gland on the skin?

Answer 1

Microbial nutrients
Urea, AA, salts, lactic acid and lipids
Acidic pH (4-6)

Question 2

Where are microbes on the skin associated?

Answer 2

Sweat ducts and hair follicles

Question 3

What are the two types of skin flora?

Answer 3

Transient = transferred from a different region of the body not usually on the skin long 
Resident = on the skin for a long time, multiply and survive

Question 4

Which three microorganisms are most commonly responsible for skin infections ?

Answer 4

staphylococcus aureus
streptococcus pyogenes
Pseudomonas aeruginosa

Question 5

What infects kidney transplant patients ?

Answer 5

cryptococcus neoformans

Question 6

What are the components of the crystalline biofilm which blocks the lumen of catheters ?

Answer 6

Struvite (magnesium ammonium phosphate)

Apatite ( hydroxylate calcium phosphate, variable proportion of the phosphate groups are replaced by carbonate)

Question 7

Why does a crystalline biofilm form ?

Answer 7

urease hydrolyses urea which forms ammonium and carbonate ions
Increasing urinary pH

Question 8

What causes the recurring urinary catheter infection ?

Answer 8

P. mirabilis

Question 9

What causes bladder infections ?

Answer 9

uropathogenic E.coli

Question 10

Is the normal skin flora gram negative or positive?

Answer 10

Thought gram-positive out competes the gram-negative

Question 11

Where on the skin has the greater species richness?

Answer 11

sebaceous

Question 12

What are the effects of an infected hip infection?

Answer 12

immobilisation and extreme pain
treat with antibiotics
Surgical revision = prosthetic removal immediately or delayed joint replacement

Question 13

What are the complications of recurrent UTI due to a catheter?

Answer 13

Remove blocked catheter with new one
New catheter place directly into alkaline urine containing bacteria and clumps of crystals
crystalline biofilm readily form on the new catheters and patients are prone to recurrent catheter blockage

Question 14

What are the consequences of recurrent urinary catheter blockage ?

Answer 14

1. Ascending influx of urine = kidney and bloodstream infection
2. from bladder stones

Question 15

How is recurrent urinary catheter blockage treated ?

Answer 15

lower urine pH by citrus drinks
Increase fluid intake
surgical removal of bladder stones if antibiotics ineffective

Question 16

bladder infections

Answer 16

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