HAI

Question 1

Define HAI

Answer 1

An infection that was not present/in its pre-symptomatic phase during time of admission and which has arisen 48h+ after admission/within 48h of discharge

Question 2

Define colonisation

Answer 2

Microbes in body not causing disease

Question 3

Give an example of a colonising microbe

Answer 3

MSSA around the nose

Question 4

Define infection

Answer 4

Microbes in the body causing disease

Question 5

Give an example of an infection

Answer 5

Same MSSA can cause UTIs, surgical site infections, ventilator assoc. pneumonia etc.

Question 6

Define cleaning

Answer 6

Physical removal of organic material and reduction in microbial load

Question 7

For which situations do we just clean?

Answer 7

Low risk, e.g. in tact skin surface, stethoscopes, beds, cots etc.

Question 8

How do we clean?

Answer 8

Water, detergent, dry properly

Question 9

Define disinfection

Answer 9

Massively reducing the microbial load (but spores remain)

Question 10

In which situations do we disinfect?

Answer 10

Medium risk situations, e.g. mucous membranes - vaginal speculums, bed pans, endoscopes

Question 11

What are the two methods of disinfecting?

Answer 11

Heat - pasteurisation (bedpans, linen etc.) & boiling (speculums, ear syringes)

Chemical - e.g. alcohol, chlorhexidine, hypochlorites, hydrogen peroxide

Question 12

Define sterilisation

Answer 12

Removal/destruction of all microbes and spores

Question 13

When would we sterilise?

Answer 13

High risk situations, e.g. surgical equipment

Question 14

What are the methods of sterilisation?

Answer 14

Steam under pressure, e.g. autoclave
Hot air oven
Gas, e.g. ethylene dioxide
Ionisation radiation

Question 15

What must you do prior to sterilisation and disinfection?

Answer 15

Cleaning

Question 16

Define outbreak of infection

Answer 16

2+ cases of an infection linked in time and place

Question 17

How many patients does HAI affect?

Answer 17

5%

Question 18

What are the possible outcomes of HAI?

Answer 18

Extended length of stay, discomfort, pain, death, disability
Increased cost
Litigation
Reduced staff morale/public confidence

Question 19

What are the most common HAIs? (in order)

Answer 19

UTIs (mostly catheter assoc.)
Surgical site infection 
RTI (esp related to intubation)
Bloodstream infections
GI infections
Skin and soft tissue infections

Question 20

Most HAI is the result of a disturbance in _______

Answer 20

Bacterial-host equilibrium

Question 21

What microbial factors make infection more likely?

Answer 21

Increased resistance, virulence, transmissibility, survival ability, ability to evade defences

Question 22

What host factors make infection more likely?

Answer 22

Devices (PVC, CVC, catheters, ventilators), break in skin, antibiotics, FB, immunosuppression, gastric acid suppression, age extremes, overcrowding, increased opportunity for infection (e.g. interventions/hands)

Question 23

What is the chain of infection?

Answer 23

Source of microbe
Transmission
Host

Question 24

What are the different forms of transmission?

Answer 24

Direct contact, e.g. staph aureus and coliforms
Respiratory droplet, e.g. Neisseria meningitidis, mycobacterium tuberculosis
Faecal-oral, e.g. c. diff, salmonella sp.
Penetrating injury, e.g. group A strep, bloodborne viruses

Question 25

How do you break the chain of infection?

Answer 25

``` Risk awareness SIPCs Hand hygiene campaigns Antibiotics steward ship Universal MRSA screening Appropriate MRSA screening PPE Vaccination and PEP Environment ```

Question 26

Define antibiotic stewardship

Answer 26

Co-ordinated programme that promotes appropriate use of antibiotics and improves patients outcomes whilst decreasing microbial resistance

Question 27

What are the two kinds of surveillance of HAI?

Answer 27

Local and national

Question 28

What is the purpose of surveillance of HAI?

Answer 28

To detect and identify a possible outbreak at earliest opportunity

Question 29

What must you do in suspected outbreaks?

Answer 29

Typing to determine if it is the same strain | Control measures

Question 30

What methods of typing can you use?

Answer 30

Antibiogram - antibiotic sensitivity pattern Phage typing - bacteriophages used to identify different strains Pyocin typing - based on pycoin production (pseudomonas) Serotyping (salmonella, pseuodomonas) - based on antigens Molecular typing - DNA

Question 31

What are the control measures implemented in outbreaks of HAI?

Answer 31

Single room isolation Cohorting Reinforcement of IPC measures Staff exclusion/decolonisation

Question 32

What is the classical presentation of c. diff?

Answer 32

Really smelly diarrhoea, abdominal pain, pyrexia, raised WCC

Question 33

What kind of colitis do you get in c. diff infection?

Answer 33

Pseudomembranous colitis

Question 34

How does c. diff survive in the environment?

Answer 34

It is spore forming

Question 35

C. diff produces two toxins - what is the significance of this?

Answer 35

Toxin negative strains do not produce disease Even toxin +ve ones can also not be symptomatic

Question 36

What is the pathophysiology behind c. diff infection?

Answer 36

Infection results from imbalance in gut flora (protective commensals reduced allowing c. diff to flourish)

Question 37

In which group of people is c. diff most common?

Answer 37

Elderly

Question 38

What drugs predispose to c. diff?

Answer 38

Antibiotics

Question 39

What is involved in the management of c. diff?

Answer 39

Stop antibiotics | Give oral metronidazole, oral vancomycin if severe/2nd line, oral fidaxomicin if 2nd episode

Question 40

Reducing use of which 4 drugs has reduced the incidence of c. diff?

Answer 40

4 Cs | Clindamycin, ceftriaxone, co-amoxiclav, ciprofloxacin