L15: Antimicrobial Resistance and Stewardship

Question 1

When were antibiotics first developed? How does this related to antibiotic resistance?

Answer 1

Antibiotics developed 2 billion to 40 million years ago

Resistance–> Similar age

Question 2

How can they determine when antibiotic resistance developed?

Answer 2

Drill down into permafrost–> 30000 years ago
(before antibiotics perscribed)
Extract bacteria
Genetic analysis to show genes with resistance

Question 3

What was the first evidence of resistance?

Answer 3

Resistance to penicillin in individuals that had never had penicillin
Naturally resistance strains that have survived because of survival of the fittest

Question 4

How does horizontal gene transfer influence resistance?

Answer 4

Bacteria able to transfer resistance genes between each other
Overtime become more and more resistant
Antibiotics select for resistance

Question 5

What effect does resistance have in a clinical setting?

Answer 5

Significant problem
Patient infected with bacteria with no antibiotics that aren’t resistant –> pan-resistance
Finding sensitive antibiotics can be difficult

Question 6

What is one of the main problems with resistance?

Answer 6

It is irreversible
Bacteria cannot be cured of resistance
New antibacteria development not happening

Question 7

What are the consequences of antibacterial resistance?

Answer 7

Treatment failure –> pan-drug resistance
Prophylaxis failure–> antibiotics prevent surgical site infections–> resistance means surgical site infections will rise and surgical operations will be reduced
Economic cost–> consequence, expensive to treat patients

Question 8

Define multi-drug resistance (MDR)?

Answer 8

Non-susceptibilty to at least one agent in three or more antimicrobial categories

Question 9

Define extensive drug resistance (XDR)?

Answer 9

Non-susceptibility to at least one agent in all but two or fewer antimicrobial categories

Question 10

Define pan-drug resistance (PDR)?

Answer 10

Non-suscpetibility to all agents in all antimicrobial categories

Question 11

Define not muti-drug resistance?

Answer 11

Isolates non-susceptible to >1 agent in <2 antimicrobial categories

Question 12

What is antimicrobial stewardship?

Answer 12

An organisational or healthcare-system wide approach to promoting and monitoring judicious use of antimicrobial to preserve their future effectiveness

Question 13

What does antimicrobial stewardship depend on?

Answer 13

Antibacterial use and resistance

Causal relationship

Question 14

What is the evidence that antibacterials cause resistance?

Answer 14

Laboratory evidence–> provides biological plausibility

Ecological studies–> relates level of antibiotic use in a population with levels of resistance

• Look at use one year, measure resistance the following year
• Not perfect as the antibiotics used may not be used in the patient that goes on to develop resistance

Individual level data–> prior antibacterial use in patient with subsequent presence of bacterial resistance (detected by culture or molecular means)

Question 15

What are the objectives of antimicrobial stewardship?

Answer 15

Ensure appropriate use of antimicrobials
Optimal clinical outcomes
Minimise toxicity and other adverse events
Reduce the cost of health care for infections
Limit the selection for antimicrobial resistant strains

Question 16

How do you go about achieving antimicrobial stewardship?

Answer 16

Requires a structure

• Multidisciplinary team and relationships to other quality/ safety teams –> drive appropriate use
• Surveillance–> process measures (what antimicrobials are being used) and outcome measure (what resistance has occurred)
• Interventions–> persuasive, restrictive and structural

Question 17

Who is involved in a multi-disciplinary team for trying to achieve anti-microbial stewardship?

Answer 17

Medical microbiologist/ infectious disease physician 
Antimicrobial pharamcist 
Infection control nurse
Hospital epidemiologist 
Information system specialist

Question 18

What is antimicrobial stewardship in relationship with?

Answer 18

Infection prevention

Environmental decontamination–> keeping the hospital clean

Question 19

What are the different types of interventions?

Answer 19

Persuasive
Restrictive
Structural

Question 20

What is meant by persuasive intervention?

Answer 20

Education–> of resistance, making sure they are only used when necessary
Consensus–> guideline of when antimicrobials should be used if needed
Opinion leaders–> influential people, lead by example
Reminders–> when drugs are started, when they should be stopped
Audit
Feedback

Question 21

What is meant by restrictive intervention?

Answer 21

Restricted susceptibility reporting –> have to have permission from microbiology
Formulary restrictions –> only certain amount of antibiotics allowed, have to request for more
Prior authorisation
Automatic stop order –> automatically stop prescription after certain time period

Question 22

What is meant by structural intervention?

Answer 22

Computerised records
Rapid lab tests
Expert systems–> drive prescribing decisions, put in patient details, tells you what to prescribe and for how long
Quality monitoring

Question 23

What is meant by process measures?

Answer 23

Measure the amount of antibiotics being used
Use a measurement called ‘defined daily dose–> widely accepted dose that will be given to a patient in a day
–> allows you to compare usage over time between different organisations
–> Divided by number of bed days to compensate for difference in size of hospitals
Also measure antibacterial classes used and appropriateness (adherence to guidelines)
Compare within the institution at different time periods and against other institutions

Question 24

How is outcome measure measured?

Answer 24

Patient outcomes: did patient survive or die?
Emergence of resistance
Clostridium difficile infections rate–> complications, measure of usage of antibiotics

Question 25

What are the challenges for stewardship?

Answer 25

Well developed in this country but…

• Need to consider long term confirmed and appropriate resources–> support still needed, still unresourced stewardship team
• Hospital leadership support–> needs challenging, still lots of clinicians that over prescribe that aren’t challenged due to their position
• Integration into organisational patient safety and quality of care structure and processes

Question 26

Which intervention appears to be most effective?

Answer 26

Restrictive tends to get results faster

Persuasive takes more time but get the same results in the long run

Question 27

Are there any unintended consequences?

Answer 27

Decrease antibiotic prescribing potential for patients to not get treatment they need–> little evidence if anything treatment seems to be more appropriate (right antibiotic for shorter period of time)