Successfully reported this slideshow.
We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime.

LQAS-based surveillance of antimicrobial resistance

Empirical antibiotic treatment requires good insight in the prevalance of antimicrobial resistance (AMR). Conventional prevalence surveys are time consuming, costly, and provide aggregated estimates. The presentation introduces the LQAS methodology to rapidly classify well-defined populations as having high- or low prevalence of AMR, facilitating appropriate antibiotic treatment strategies at a local level.

Related Audiobooks

Free with a 30 day trial from Scribd

See all
  • Be the first to comment

  • Be the first to like this

LQAS-based surveillance of antimicrobial resistance

  1. 1. Lot Quality Assurance Sampling A tool for surveillance of antimicrobial resistance? F R AN K VAN L E T H A S S O C I A T E P R O F E S S O R O F G L O B A L H E A L T H A M S T E R D A M U N I V E R S I T Y M E D I C A L C E N T E R S , L O C A T I O N A M C , U N I V E R S I T Y O F A M S T E R D A M A M S T E R D A M I N S T I T U T E F O R G L O B A L H E A L T H A N D D E V E L O P M E N T
  2. 2. www.aighd.org Antimicrobial resistance kills
  3. 3. www.aighd.org Outline Measuring prevalence of antimicrobial resistance Concept of Lot Quality Assurance Sampling (LQAS) LQAS-based AMR survey in Indonesia
  4. 4. www.aighd.org AMR control needs measurement of AMR prevalence 4
  5. 5. www.aighd.org Current AMR surveillance largely laboratory-based 5
  6. 6. www.aighd.org AMR surveillance: current 6 Laboratory based AMR surveillance Conventional LQAS Selection bias Representative Population based
  7. 7. www.aighd.org Laboratory-based surveillance overestimates prevalence of AMR
  8. 8. www.aighd.org AMR surveillance: preferred 8 Laboratory based AMR surveillance Conventional LQAS Selection bias Representative Population based
  9. 9. www.aighd.org Repeated AMR surveys limited by large sample sizes 9
  10. 10. www.aighd.org AMR surveillance: A solution 10 Laboratory based AMR surveillance Conventional LQAS Selection bias Representative Population based Copyright: Massachusetts Biotechnology Council
  11. 11. LOT QUALITY ASSURANCE SAMPLING
  12. 12. www.aighd.org Lot Quality Assurance Sampling (LQAS) Derived from setting of manufacturing ◦ Quality assurance strategy Main question: Is the threshold for ”adequate quality” met? Assessment based on small samples from well-defined batches of goods 12
  13. 13. www.aighd.org The process of LQAS LOT Sample Decision rule Classification
  14. 14. www.aighd.org LQAS-based AMR surveillance Done in a classification framework Is the AMR prevalence in the population above or below x % Framework does not include issues on power or statistical significant difference ◦ Use concept of misclassification Lot can be any well-defined grouping ◦ Region ◦ Facility ◦ Subpopulation Classification “high AMR” should lead to an intervention 14
  15. 15. www.aighd.org Allowable misclassification True “low” prevalence classified as “high” and vice versa Misclassification unnecessarily implements or withholds intervention ◦ Both equal weight? 15
  16. 16. www.aighd.org Typical LQAS sample sizes LQAS definition Sample Size Decision rule Misclass L as H Misclass H as L Misclass Tot 2 - 10 76 4 6.6 4.7 11.3 5 - 20 44 5 6.7 4.4 11.1 10 - 20 112 16 9.2 4.7 13.9 10 - 25 55 9 9.5 4.5 13.9 15 - 25 139 27 9.3 5.0 14.3 15 - 30 70 15 9.4 4.1 13.5 16
  17. 17. TEST CHARACTERISTICS OF LQAS 17
  18. 18. www.aighd.org Theoretical lots from conventional surveillance 18 1 2 3 4 5 1 2 3 4 5
  19. 19. www.aighd.org LQAS classifications from repeated draws 19 1 LQAS classification Draw 1 Draw 2 Draw … Draw 999 Draw 1000 LQAS classification LQAS classification LQAS classification LQAS classification
  20. 20. www.aighd.org Operator curve: classification as high resistance 0 20406080 100 0 2 5 10 20 30 40 50 60 70 80 90 100 True prevalence of resistance (%) 2 - 10 5 - 20 10 - 20 10 - 30 20 - 50 30 - 50 20
  21. 21. www.aighd.org Test characteristics 21 LQAS definition Sensitivity Specificity 2 - 10 100 44.1 5 - 20 99.9 85.0 10 - 20 100 98.9 10 - 25 99.6 85.1 15 - 25 98.8 80.6 15 - 30 99.9 87.1
  22. 22. LQAS-BASED SURVEILLANCE 22
  23. 23. www.aighd.org Prospective LQAS-based AMR surveillance: identifying local variations outpatients inpatients 1 2 3 4 5 6 7 8 9 10 11 Ciprofloxacin Levofloxacin Trimethoprim- sulfamethoxazole Nitrofurantoin Amoxicillin/clavulanic acid Ampicillin/sulbactam Piperacillin/tazobactam Cefixime Ceftazidime Ceftriaxone Amikacin Gentamicin Fosfomycin$ Ertapenem Meropenem 23
  24. 24. www.aighd.org Titration: assessing multiple upper boundaries Clinic 1 Clinic 2 Clinic 3 Levofloxacin 2 - 10 high high 5- 20 high high high 10- 25 high high 15 - 30 high high Tigecycline 2 - 10 low high 5- 20 low low low 10- 25 low low 15 - 30 low low 24
  25. 25. www.aighd.org Titration: assessing multiple upper boundaries Clinic 1 Clinic 2 Clinic 3 Levofloxacin 2 - 10 high high 5- 20 high high high 10- 25 high high 15 - 30 high high Tigecycline 2 - 10 low high 5- 20 low low low 10- 25 low low 15 - 30 low low 25
  26. 26. CONCLUSION 26
  27. 27. www.aighd.org Conclusion LQAS promising approach to measure AMR resistance ◦ Timely ◦ Local variation ◦ Affordable Combining classifications lots into conventional prevalence estimates possible ◦ Needs careful design considerations Facilitates move from laboratory- to population-based surveillance ◦ Anticipated in GLASS 27
  28. 28. www.aighd.org Contact and slides Email: f.vanleth@aighd.org Twitter: @fvlscience Link to slides posted on frankvanleth.com

    Be the first to comment

Empirical antibiotic treatment requires good insight in the prevalance of antimicrobial resistance (AMR). Conventional prevalence surveys are time consuming, costly, and provide aggregated estimates. The presentation introduces the LQAS methodology to rapidly classify well-defined populations as having high- or low prevalence of AMR, facilitating appropriate antibiotic treatment strategies at a local level.

Views

Total views

59

On Slideshare

0

From embeds

0

Number of embeds

0

Actions

Downloads

1

Shares

0

Comments

0

Likes

0

×