9. Antimicrobial Stewardship Flashcards
1
Q
Antimicrobial stewardship
A
- ISDA: “…coordinated interventions designed to improve & measure the appropriate use of antimicrobials by promoting the selection of the optimal antimicrobial drug regimen, dose, duration of therapy, & route of administration
- Improve appropriate antimicrobial use & therefore patient outcomes
- NOT the intention to solely reduce antimicrobial use
2
Q
Why do we need Antimicrobial Stewardship (AMS)?
A
ALL ANTIMICROBIAL USE DRIVES HARM
- Patient level harm
- Population level harm
Direct adverse effects on patients:
- Allergies, side effects, supra-infections
- Antimicrobial resistance
Adverse effects on community:
- “The problem of the commons” aka global cost
- Antimicrobial resistance
3
Q
Discovery of Antimicrobial Resistance (AMR)
A
- Penicillin (1943) – 3 years
- Tetracycline (1950) – 1 year
- Erythromycin (1953) – 15 years
- Methicillin (1960) – 2 years
- Gentamycin (1967) – 12 years
- Vancomycin (1972) – 16 years
- Imipenem (1985) – 13 years
- Ceftazidime – 2 years
- Levofloxacin (1996) – 0 years
- Linezolid (2000) – 1 year
- Daptomycin (2003) – 2 years
- Ceftaroline (2010) – 1 year
4
Q
Antimicrobial use = AMR
A
- Antimicrobial use is proportional to antimicrobial resistance
- NZ is a high user of antibiotics, and the rates are slightly decreasing
5
Q
Individual AMR
A
- After taking a macrolide for CAP, a patients likelihood that their next infection is related to a resistant organism is increased significantly (10x in the week after & 2x 6 months after)
- For UTIs being treated with amoxicillin or trimethoprim, 30 % increase in resistant infections are seen a year after taking a single course of antibiotics
6
Q
Patient outcomes
A
- Although there are many different types of antibiotics that can be used, if they’re colonised with more resistant bacteria, they will have poorer outcomes
- Increased cost and length of hospital stay, increased mortality & delay in appropriate therapy
7
Q
Economic costs by 2050:
A
- 1.1 – 3.8% reduction in total global GDP
- +$0.3 trillion increase p/a on health
- ~100 trillion in total
8
Q
Drivers of antimicrobial use
A
Prescribers: \+ Clinical need \+ Anxiety/concerns - Patient expectations - Economic – esp. agriculture - Lack of alternatives – e.g. phage therapy, monoclonal antibodies
9
Q
Improving antimicrobial use
A
- MOH: New Zealand Antimicrobial Resistance Action Plan
2. WHO: Global Action Plan on Antimicrobial Resistance
10
Q
Governance
A
- Ensure executive awareness & responsibility
- Regular review of quality indicators of AMR
- Regular improvement in antimicrobial use
- Appropriate resourcing
- Primary Care: DHBs, PHOs, Aged care etc
- Secondary care: DHBs, Directories
11
Q
Population interventions
A
- Surveillance of antimicrobial use
- Formulary, restriction & control
- Review & feedback to prescribers
- Education
- Development of antimicrobial guidelines
12
Q
- Surveillance of antimicrobial use
A
- In 2017, almost 1/3rd (32.7%) of the 21,034 prescriptions that were assessable did not comply with guidelines
- In addition, ¼ of the 24,987 prescriptions that were accessible were classified as inappropriate
- …but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meagre & satisfactory kind…
13
Q
- Formulary, restriction & control
A
- Simple, effective, evidence-based intervention
- Set a list of approved medicines:
+ WHO: Access, Watch, Reserve (“AWaRe”)
+ PHARMAC: HML - Introduce controls to access
- Funding, physical removal, expert approval
14
Q
- Review & feedback
A
HARD, effective, evidence-based intervention
Audit & feedback to prescribers:
- Quality improvement cycle
- Adherence to guidelines
- Documentation of indication & review
Feedback/reporting to target audience:
- To prescriber (RMO, SMO, GP)
- To prescribers’ team
- To management group
- To governance
15
Q
Education to users
A
- Undergraduate
- Continuing professional development
- Easy to provide but limited benefit
- Service specific messaging
- In combination with audit & feedback
16
Q
Education to END users
A
Continual education is important to change culture:
- Children through to adults
- Understand disease processes
- Understand benefits & risks
Consistent managing:
- Stop direct to consumer advertising
- Encourage vaccination
- Taking antimicrobials correctly – “as directed”
17
Q
Patient level interventions
A
- Use of guidelines
- Reporting lab results
- Optimising therapy
- Preventing infection pharmaceutically
- Improving medical records
- Assessing antibiotic allergies
18
Q
- Antimicrobial guidelines
A
- Adherence reduces mortality & length of stay
- Best guess or empiric therapy for disease states or specific organisms
- Written by expert groups
- Used to treat a patient based on population data
- International guidelines useful for e.g. PKPD & durations
Local guidelines preferable:
- Difference in causative organisms (rare)
- Difference in susceptibility (common)
How local is local?
- International – Australia, South Africa, USA, UK?
- National > Regional > Hospital > Unit
- NZ > Auckland > ACH > BMTU
19
Q
Examples of guidelines
A
International:
- WHO TB
- European Society of Cardiology IE
- BSAC (UK) or TG (Australia)
Local:
- National BPAC community guidelines
- Health pathways (GP guidelines)
- Hospital guidelines (ADHB Script; Southern Regional)
20
Q
Key components in guideline development
A
- Causative pathogens in disease – e.g. E. coli in cystitis, S. pneumoniae in CAP
- Local susceptibility of pathogens – Antibiograms
- Dosing regimen for optimal PKPD – e.g. cefuroxime 750 mg IV q8h for S. pneumoniae or 750 mg IV q6h for K. pneumoniae
- When to start & stop
- Patient factors
+ Allergies
+ PK variations e.g. Vd, CL, F (Obesity, renal impairment, functioning gut)
+ Immunosuppression
21
Q
ADME
A
- Absorption – route of administration & bioavailability (vancomycin)
- Distribution – solubility & protein binding (rifampicin)
- Metabolism – activation of pro-drugs (colistin)
- Elimination – hepatic or urine (UTI)
22
Q
Site of infection - “penetration”
A
- Pharmacokinetics
- Penetration may be governed by distribution OR elimination
- Does the antimicrobial get to the site of infection in sufficient concentrations?
- Usually studies in ‘normal’ tissue e.g. abdominal or skin
- Difficult/sanctuary sites e.g. CSF, eyes, prostate
23
Q
When to start?
A
- Dependent on infection being treated
- Critically unwell patients (sepsis/septic shock)
+ Timeline of effectiveness antibiotics critical 7% increase in mortality/hour - Less severe presentations/less urgency
24
Q
When to stop?
A
- Determining a stop date or duration of therapy
- Population studies
- Patient response “complete the course”
- Biomarkers e.g. temperature, CRP, PCT
25
Q
Guideline non-adherence
A
- Prescribing to adhere to guidelines
- Developed by specialists to provide best evidence
Why wouldn’t you?
- Availability & ease of use
- Perceived correctness of content
- Need for variation based on patient features
- Clinical judgement trumping guideline
- Time pressure
- Past experience/teaching is basis of practice
Changing people’s opinions are not easy to do
26
Q
Reporting microbiology results
A
- Selected microbiology reporting
- Nudge theory
- Allows narrowing of spectrum
- Results to be considered in patient view
- Clinical condition & site of infection
- Relationship to timing of antimicrobials
+ Antibiotics or sample first? - Effect of PKPD
27
Q
Optimising the route - IVOS
A
- Changing patients from IV to oral
- Reduced length of stay, healthcare costs, secondary infections, line associated complications, nursing time
- Increased patient satisfaction
Criteria to change oral OR to continue IV
- Absorption of drug – patient & bioavailability
- Site of infection e.g. endocarditis
- Type of host e.g. neutropenic
- Does this all optimise PKPD?
Recommended by a pharmacist … or DONE by a pharmacist
28
Q
Optimise concentration
A
- Measuring a concentration removes estimation of relationship to population-based dosing
- Aiming for a PKPD target concentration “TDM”
- Efficacy or toxicity or both
- Adjust the dose accordingly
- E.g. Optimising vancomycin concentrations to efficacy AUC 400 improves renal toxicity by reducing AUC > 600-700
29
Q
Optimise prevention
A
Vaccination to prevent infection (& thus antimicrobials)
Use of antimicrobial to prevent infection:
- Risk due to defect in immune system or response
- Surgical setting – incision
- Medical setting – medicines, infection, pathology
30
Q
Optimise prevention - surgical
A
Aim: Prevent surgical site infections (SSI)
- Likely to have beneficial bacterial contamination or
- Likely to have catastrophic effects
Similar considerations as starting empiric therapy
- Common pathogens causing SSI & their susceptibilities appropriate dosing & intervals
- Timing is critical: Optimally within 60 minutes before incision (“knife to skin”) … administration issues?
- Mostly single dose therapy appropriate, certainly not more than 24 hours
- If patients on treatment antimicrobials; appropriate prophylaxis still necessary to optimise timing & concentrations
- Re-dosing when concentration drops; blood loss or surgery > t1/2
31
Q
Optimise prevention - medical
A
- Aim: To prevent (initial or relapse) bacterial, viral, fungal or protozoal infections
- Medicines e.g. chemotherapy, corticosteroids
- Infection e.g. HIV, HSV
- Pathology e.g. Splenectomy, rheumatic fever
32
Q
Optimise record keeping (?!)
A
- Documentation of key quality indicators
- Write down the indication for the antimicrobial
- Write down a stop or review date
- Allows review by others e.g. a pharmacist
- Encourages the prescriber to consider what they are doing
33
Q
Optimise “allergies”
A
- Common problem is prevalence of “allergy”
- Differentiate between allergy & ADR
- Most common antimicrobial allergy recorded is penicillin
Poorer outcomes compared to non-allergic patients:
- Increased mortality
- Increased morbidity
- Increased broad-spectrum use (some inferior)
- Increased length of stay in hospital
- Increased healthcare costs
- Highly over-estimated in literature
- All antimicrobial allergies should be reviewed at prescribing or admission
De-labelling penicillin allergy:
- ~65% of patients de-labelled (MMH)
- ~80% with questions/history alone
- ~20% with skin testing or oral challenge
- Update documentation
34
Q
A principled use of antimicrobials
A
- Make an accurate diagnosis
- Take microbiology samples (and consider past microbiology)
- Start empiric guideline-adherent microbiology
- Adjust therapy accordingly
- Review patient progress & microbiology
- Adjust therapy accordingly
35
Q
Making a diagnosis
A
- Clinician to recognise infection
- Clinical examination & history
- Undertake appropriate investigations
- Interpret laboratory results:
+ Contamination/colonisation/infection - Consider likely pathogens & how to treat
36
Q
Starting antimicrobials
A
- “Start smart then focus”
- Directed therapy or empiric therapy
- Directed therapy
+ Known pathogen +/- susceptibility - Empiric therapy from guidelines
- Likely pathogens involved in disease e.g. E. coli predominant in pyelonephritis
- Local susceptibility patterns of pathogens e.g. Auckland 2018 E. coli 48%(c)/38%(h) S to amoxicillin
- Appropriate regimen for susceptible organisms e.g. cefuroxime 750 mg IV q8h
- Appropriate duration of treatment e.g. 10 days for pyelonephritis
- Difference depending on severity of illness
37
Q
What about a “severe” infection?
A
- Severity of illness
- Sepsis or septic shock - Current definition using SOFA score
Disease specific severity scoring systems
- E.g. CURB-65 for CAP demonstrates increasing mortality
- E.g. Cellulitis treatment pathway with factors of failure
38
Q
Adjusting therapy
A
- Initial therapy may need to be narrowed or broadened from results e.g. usually starting broad & de-escalating spectrum once pathogen identified
- Route of administration could be changed e.g. IVOS
- Deciding on a duration of therapy; over & under-treatment risks
- Any change in therapy – start antimicrobial review again (PK/PD)
