MICRO: Healthcare associated infections

Question 1

What are HAI?

Answer 1

Healthcare associated infections; they are categorised by organism (1) or by syndrome (2).

(used to be hospital acquired infections)

Question 2

How common are HAIs in the UK?

• 8%
• 22%
• 40%
• 55%

Answer 2

8% - approximately 8% of patient have a HAI at any one time

Question 3

List some syndromes of HAI.

Answer 3

Question 4

List some organisms causing HAI.

Answer 4

Question 5

How many people die as a result of HAI each year in Europe?

Answer 5

37,000

Question 6

Which syndromes are these infections associated with?

• MRSA
• C diff
• E coli
• MSSA
• R gram -ve
• Yeast/candida

Answer 6

Question 7

What are the 3 most common HAI syndromes?

Answer 7

HAP > surgical site infections> UTI > BSI > GI

NB: this may vary with locations/wards.

Question 8

What % of HAI are made up by C diff and MRSA?

Answer 8

15% of all HAI

Question 9

Which is the most common syndrome of HAI?

• Bloodstream infections
• Norovirus gastroenteritis
• Hospital acquired pneumonia
• Urinary tract infection with catheter
• Clostridium difficile

Answer 9

HAP

Question 10

What was the purpose of the Hospital Microbiome Project? What was the result?

Answer 10

Determine where the organisms in hospital were originating - collected samples from surfaces, air, staff and patients. Aimed to determine which parameters were most important.

• 1st day - from surfaces in room to patient
• 2+ days - from the patient to the room, patient’s microbiome takes over patient’s space

Question 11

Where do organisms in a hospital come from?

Answer 11

Mainly the environment

Question 12

C. difficile is?

• Gram positive anaerobe
• Gram negative aerobe
• Gram variable coccobacillus
• Gram positive spore-forming anaerobe
• Other not listed

Answer 12

C. difficile is a Gram-positive spore-forming anaerobe that colonises the gut. It produces toxins to have its effect and cause disease.

Question 13

What causes diarrhoea/colitis in C diff infection?

Answer 13

• Toxinotype III/ Toxins A and B
• Pro-inflammatory
• Cytotoxic
• Enterotoxic

Question 14

What is the range of symptoms in C difficile?

Answer 14

Mild diarrhoea/asymptomatic –> severe colitis with dehydration, pseudomembraneous colitis and perforation

Question 15

What is the assessment for antibiotics for C diff infection?

Answer 15

Severe C difficile - oral vancomycin (used to be metronidazole)

Question 16

What is the use of fidaxomysin?

Answer 16

Question 17

What is a non-drug management for C difficile?

Answer 17

Faecal transfer

Question 18

What is the most common UTI in the community and in hospital?

Answer 18

Community - E coli (82%)

Hospital - E coli(55%) but more due to other causes too.

Question 19

What % of catheters causing UTI become colonised within the first 96 hours?

Answer 19

60%

Question 20

What 3 groups of factors influence risk for surgical site infection (SSI)?

• Staff, ward, category, day of week
• Host defence, host gender, surgeon gender
• Host defence, wound environment, pathogens
• Virulence of pathogens, antibiotics used, type of suture
• Experience of surgeon closing wound, mask used by theatre staff, music played in theatre

Answer 20

Host defence, wound environment, pathogens

Question 21

What are the main resistance mechanisms in resistant gram negatives?

Answer 21

1. Chromosomal
2. Plasmid mediated

(E coli< Klebsiella < Enterobacter etc)

Question 22

Which 4 infection control strategies are used to reduce HAI?

Answer 22

• Reduce number of bugs (i.e. sterilise, washing, etc.)
• Reduce number of resistance bugs (i.e. screen patients)
• Prioritise side rooms + reduce transmission of bugs (i.e. for fever + rash in ED; for homeless man with cough and abnormal CXR)
• Medical education (i.e. hand cleaning technique)

Key strategies:

1. measure infection
2. analyse for trends
3. feedback and alter practice
4. improve infection control and reduce infection

Question 23

What does this gram stain show?

Answer 23

Gram +ve cocci in clusters = MRSA

Question 24

What are the implications of MRSA infection?

Answer 24

Question 25

Often patients are colonised and therefore screened for MRSA on admission. How are they decolonised?

Answer 25

Chlorhexidine washes

Question 26

Why are HAI becoming more common?

Answer 26

• We do more invasive procedures
• Prosthetic and implantable devices
• Obesity
• Diabetes
• Extremes of age
• Immunosuppression
• Emerging organisms and resistance

Question 27

How is environmental hygiene ensured in hospitals?

Answer 27

• Environmental hygiene and cleaning
• Control of environmental sources e.g. testing water (Legionella- cooling towers, Pseudomonas- all water)
• Building works (Aspergillus)
• Negative pressure isolation- protect others from an infectious patient with airborne infection
• Positive pressure isolation- protection of transplant patients from organisms outside of the room

Question 28

What % of HAI are preventable?

Answer 28

33%