BSAC Susceptibility Testing Residential Workshop

Transcription

1 BSAC Susceptibility Testing Residential Workshop EUCAST Further developments & UK specific advice Insert name of presentation on Master Slide Mandy Wootton

2 Consultation process National Breakpoint Committees F, G, N, NL, S, UK EUCAST Steering Committee Chairman, Scientific Secretary, Clinical Data Co-ordinator, 6 Breakpoint Committee reps 2 General Committee reps, 2 visiting GC reps EUCAST General Committee 35 National reps, FEMS and FESCI reps EUCAST Subcommittees Antifungals, Veterinary agents, Whole genome sequencing, Expert Rules, Anaerobes, Resistance mechanisms National Antimicrobial Susceptibility Testing Committees (NACs) Individual experts, ESCMID Study Groups, ECDC Networks, Industry

3 EUCAST decision making process Steering committee evaluates available data and proposes breakpoints (and other decisions) Consultation with general committee and national committees (NACs) on proposed decision revision of the proposal Public consultation (EUCAST webpage) after which criticism and responses are published revision of proposed decision Final decision (and for breakpoints rationale document) published

4 National AST Committees (NACs), August 2014 Yes In the process of forming a NAC No Norway No information Portugal Ireland Spain Great Britain France Netherlands Denmark Belgium Luxembourg Germany Switzerland Czech Republic Poland Finland Estonia Latvia Lithuania Slovakia Belarus Moldova Austria Hungary Romania Slovenia Croatia Bosnia - Serbia Herze- Monte- Bulgaria Italy govina negro Macedonia Albania Greec e Ukraine Turkey Russia Countries not on map Malta Australia Iceland Israel South Africa USA Brazil Morocco

5 Implementation of EUCAST breakpoints

6 EUCAST remit... To determine clinical breakpoints for bacteria and fungi together with EMA as part of the process for the approval of new agents Review established clinical breakpoints To determine epidemiological cut-off values (ECOFFs) for bacteria and fungi To develop and standardise AST in Europe (methods, QC, education) To act as an expert committee for EMA, ECDC, EFSA and ESCMID

7 EUCAST breakpoint tables Published every January Yellow denotes change Guideline documents published throughout the year Rationale documents

8 Daptomycin & enterococci March 2016 No breakpoint exisits at present Daptomycin is used in enterococcal endocarditis Daptomycin marketed for SSTI in Europe PKPD data insufficient at this time to produce a breakpoint Use ECOFFs for guidance

9 Colistin method of testing Increasingly used so susceptibility testing increased Current guidelines (BSAC/EUCAST): disc diffusion not recommended Disc criteria removed from BSAC v 2011 Unable to detect low level resistance Disc criteria removed in CLSI in 1981 Unable to detect low level resistance

10 Colistin - Problematic susceptibility testing MIC testing also problematic Large molecule: diffuses slowly in any diffusion test Cationic: adheres to any negatively charged plastic Colistin methanesulfonate sodium (CMS): BPs rely on PKPD data Comparison of methods 50 MDR isolates (COL R) Adding a surfactant (Tween-80) is problematic Hindler & Humphries JCM 2013; 51

11 Colistin - Problematic susceptibility testing Review by a joint CLSI-EUCAST colistin working group Gradient strips give lower MICs Perform BMD for most reliable result In non treated polystyrene trays April 2016 No Tween 80 Colistin & NOT CMS used Other methods are being tested 2016

12 Fosfomycin: Problematic testing Fosfomycin is difficult to test with all methods Glucose-6-phosphate required in media Agar dilution is reference method Disk & gradient strip difficult to read Kasse definition: >5 colonies per cm 2 Disc labelling & concentrations vary Antimicrobial Discs Manufacturer Code Confirmed Fos content Confirmed G6P content Fosfomycin MAST FOS50C 50ug 50ug Fosfomycin/trometamol MAST FOT ug 50ug Fosfomycin MAST FOT200C 200ug 50ug Fosfomycin/trometamol Oxoid CT ug 50ug Fosfomycin Oxoid CT ug 50ug Fosfomycin Liofilchem FOS 50ug 50ug Fosfomycin Liofilchem FOS 0ug 50ug Fosfomycin Liofilchem FOS 200ug 50ug Fosfomycin BD FOS ug 50ug Fosfomycin BD 50ug 0 Fosfomycin BD 50ug 50ug

13 Difficult tests: Fosfomycin Fosfomycin is difficult to test with all methods Glucose-6-phosphate required Agar dilution is reference method 200ug disk + G-6-P Difficult to read Kasse definition: >5 colonies per cm 2 Antimicrobial Discs Manufacturer Code Confirmed Fos content Confirmed G6P content Fosfomycin MAST FOS50C 50ug 50ug Fosfomycin/trometamol MAST FOT ug 50ug Fosfomycin MAST FOT200C 200ug 50ug Fosfomycin/trometamol Oxoid CT ug 50ug Fosfomycin Oxoid CT ug 50ug Fosfomycin Liofilchem FOS 50ug 50ug Fosfomycin Liofilchem FOS 0ug 50ug Fosfomycin Liofilchem FOS 200ug 50ug Fosfomycin BD FOS ug 50ug Fosfomycin BD 50ug 0 Fosfomycin BD 50ug 50ug

14 AST results vs. WGS Resistance genes NOT likely, but results are uncertain Resistance genes likely, but results are uncertain Read at 1mg/L or 128mg/L?

15 Can we give guidance for reading Fosfomycin disk & gradient strips Defined set of isolates (WGS) Agar dilution, broth microdilution, disk & gradient strip. Using same 0.5 McFarland inoculum At 5, 7 & 8 CFU/mL Fosfomycin is difficult to test with all methods Compare results Expected Late Summer 2016

16 Agents without EUCAST breakpoints & under consideration Temocillin Nitroxoline Spiramycin Cefoperazone-sulbactam Currently EUCAST is preparing a list of all agents available worldwide with explanation for why they do not have breakpoints

17 EUCAST disk diffusion method development Neiserria gonorrhoeae Anaerobes Kingella kingae... Coming soon Aerococcus spp...coming soon

18 N. gonorrhoeae EUCAST disk method not available Recommend MIC methods using manufacturers instructions Media not available in UK GC agar base + 1% isovitalex 1% haemoglobin OR Chocolate Mueller Hinton agar Continue with BSAC disc method in interim

19 Anaerobes EUCAST disk method not available Recommend MIC methods using manufacturers instructions Media not available in UK Brucella agar + vitamink + haemin Continue with BSAC disc method in interim

20 Organisms with no Breakpoints and EUCAST test method Aerococcus spp. On-going Kingella kingae Nocardia spp. Aeromonas spp. Vibrio spp. Streptomyces spp. Leuconostoc spp. Lactobacillus spp. Pediococcus spp. Other HACEK organisms From 2016

21 Aerococcus spp. & Kingella kingae disk diffusion EUCAST disk diffusion method for fastidious organisms MH-F agar McFarland 0.5 inoculum 5% CO h incubation Calibration with broth microdilution MH-F broth

22 No of isolates No of isolates No of isolates No of isolates A. urinae & A. sanguinicola Benzylpenicillin 1 unit Ciprofloxacin 5 µg Inhibition zone diameter (mm) Inhibition zone diameter (mm) A. urinae A. sanguinicola Inhibition zone diameter (mm) A. urinae A. sanguinicola Inhibition zone diameter (mm)

23 No of isolates No of isolates No of isolates No of isolates Kingella kingae 16 Benzylpenicillin 1 unit 18 Cefotaxime 5 µg Inhibition zone diameter (mm) Inhibition zone diameter (mm) Tetracycline 30 µg Inhibition zone diameter (mm) Trimethoprim-sulfamethoxazole 25 µg Inhibition zone diameter (mm)

24 Topical antimicrobials

25 Direct susceptibility testing Advantages: Early results for pure organisms More appropriate antimicrobial therapy Narrow spectrum antimicrobial earlier (Start Smart & Focus) Disadvantages: Inoculum not controlled Mixed cultures ph variation or substances in samples which affect results

26 Direct susceptibility testing Unreliable results No validated methods for direct testing Repeat tests on pure cultures Validate in house (compare with standardised test) 30 urines 3 staff

27 Evaluation of disks from nine manufacturers Abtek BD Bio-Rad Bioanalyse HiMedia Liofilchem Mast Oxoid SirScan Project layout 150-mm plates 16 antimicrobial disks Each disk is tested with Same inoculum Same incubation Same reader 3 repetitions per disk and QC strain

28 Evaluation of disks from nine manufacturers Benzylpenicillin 1 unit S. pneumoniae ATCC Tobramycin µg E. coli ATCC 25922

29 Evaluation of disks from nine manufacturers Mean values from triplicate testing of each disk against QC strain Results categorised: Disks with occasional reading out of range marked with asterisk After performed once Manufacturers asked to submit further disks

30 Results of first evaluation

31 Results of Second evaluation

32 Conclusions There are significant differences in antimicrobial activity in disks from different manufacturers It is crucial for laboratories to perform internal QC, repeating any out of range. Values should be close to target (±1mm) Disk manufacturers must continuosly review manufacturing process. QC should be close to target

33 Early reading of disk tests 18 h E. coli with Cefotaxime 5ug h

34 No of readings No of readings No of readings Early reading of disk tests 6 h incubation 8 h incubation Inhibition zone diameter (mm) Inhibition zone diameter (mm) h incubation Inhibition zone diameter (mm) Poorer separation between wild type and non-wild type with short incubation time Testing of additional isolates with known resistance mechanisms is ongoing

35 Subcommittees - VetCAST to determine antimicrobial breakpoints specific to the veterinary field to harmonize veterinary antimicrobial susceptibility testing in the EU to provide education on antimicrobial susceptibility testing and antimicrobial therapy in the veterinary field in Europe to initiate and coordinate EU research aimed at filling the current gaps in veterinary antimicrobial susceptibility testing to ensure that antimicrobial susceptibility testing protocols and interpretive criteria are freely accessible online through the EUCAST website

36 Subcommittees Role of Whole Genome Sequencing in AST of Bacteria Literature review on the role of WGS in antimicrobial susceptibility and resistance testing of bacteria Determine the possible sensitivity and specificity compared to routine standard phenotypic AST determine how WGS may be applied in routine clinical laboratory practice and the likely implications for phenotypic and other genotypic methods of AST now in use determine the epidemiological implications of use of WGS to detect antimicrobial resistance determine the clinical implications of WGS in antimicrobial susceptibility testing for the selection of antimicrobial therapy determine the principles of how the result of WGS for AST would be best presented to clinical users define the drivers and barriers to routine use