L40 Healthcare assoc infections

Question 1

What is a CA-UTI, what are the risk factors for it

Answer 1

Illness caused by bacterial/yeast infection associated with urinary catheter - it interferes with normal bladder function. It is a marker of the illness being complex- being at a higher mortality risk.

Increased risk for

• women
• increased duration of catherisation,
• poor care/handling of catheter.

Question 2

How do you recognise and diagnose a CA-UTI- what are things that are not important

Answer 2

Diagnostic is presence of bacteria in the urine. Culture will usually show 1 species. eg. E coli, GNB, Pseudomonas Aeruginosa.

Specific UTI symptoms may be lacking so exclude other sources.

Not helpful: not diagnostic

• presence of pyuria - but absence points a different direction
• presence/absence of cloudy/smelly urine

Question 3

What strategies can help reduce CA-UTI which not helpful (5 each)

Answer 3

Help:

• Avoid catheter use
• Insert using aseptic technique
• remove
• appropriate care
• condom catheters for men

Not help

• antibiotic prophylaxis
• antbiotics in urine bag
• other prophylactics
• catheter irrigation
• regular testing

Question 4

How should CA-UTI be treated

Answer 4

The catheter removed if possible - there may be persisting symptoms of cystitis due to abrasion of the urethra, and bladder collapse from the catheter but after a few days take another urine sample to culture.

Question 5

What are the main types of device associated infections :

Answer 5

UTIs from bladder catheter

Blood stream infections: indwelling vascular catheter

Pneumonia : mechanical ventilation

High mortality with heart assist devices

Question 6

How do bacteria stick to surface of device

Answer 6

Biofilm: Microbial community of cells embedded in a matrix of extracellular polymeric substance that attach to a substrate or each other,

Question 7

What are the device factors resulting in infection

1/ 3 factors for pathogenesis of device associated infections

Answer 7

1. Material, PVC worst, silicon best

2.Source:
synthetic > biomaterial

3.Surface of device: textured > smooth

4. Shape:
   polymeric tubing > wire mesh

Question 8

What are the Host factors resulting in infection

1/ ​3 factors for pathogenesis of device associated infections

Answer 8

1. Lot of sticky ECM proteins in the blood = form a matrix on surface for bacteria to stick to
   eg. fibronectin
2. Immunosuppressed = greater risk

Question 9

What are the Bacterial factors resulting in infection

1/ ​3 factors for pathogenesis of device associated infections

Answer 9

1. Having non specific ability to manipulate surface charges, hydrophobicity
2. Adhesive proteins (MSCRAMMs) which bind to ECM proteins from patient on surface
3. Polysaccharide intercellular adhesin: better clumping together producing the gluey material

Question 10

What are the most common organism to cause device assoc infection

Answer 10

Gm + (mainly)
Staph epidermidis
Staph aureus

Gm -
Escherida Coli

Fungi:
Candida

Question 11

What makes treating biofilm associated bacteria hard

Answer 11

1. Antibiotics can’t reach bacteria deeper in the biofilm
2. Ones on the outside have change of phenotype, to reduce metabolism and cell surface properties so that its more resistant to antibiotics.
3. These persister cells are specialised in surviving and can revert to metabolism version becoming susceptible again when on agar so hard to do susceptability testing
4. Blood tests may be - for bacteremia after antibiotic but bacteria inside the film may survive.

Question 12

How can cannula infection be prevented

- treated with appropriate antibiotic

Answer 12

• reconsider requirement - remove unecessary
• handwashing before and after, place correctly under aseptic technique
• monitor carefully for signs of infection
• avoid femoral site bc of the increased density of pathogenic gut bacteria, harder to keep clean.