Automated systems: an overview Robin A Howe Cardiff Insert name of presentation on Master Slide

AST standards MIC taken as standard measure of susceptibility Agar dilution Broth dilution Microbroth dilution

ISO standard Broth microdiluion Mueller-Hinton Broth Inoculum 5x105 cfu/mL

AST standards MIC taken as standard measure of susceptibility Agar dilution Broth dilution Microbroth dilution S/I/R Breakpoints defined by BSAC/EUCAST/CLSI

AST standards MIC taken as standard measure of susceptibility Agar dilution Broth dilution Microbroth dilution S/I/R Breakpoints defined by BSAC/EUCAST/CLSI MIC/BP supplemented by “expert rules” for clinical use

The rationale for automated systems More reliable AST results ?closer to “standard” Reduced scope for “user” error Reproducible Improved ID linked to AST Embedded expert rules Automated systems: an overview

Identification required for interpretation of BP & expert rules

Welsh variability in ID of Enterobacter/Klebsiella/Serratia

The rationale for automated systems More reliable AST results Improved ID linked to AST Embedded expert rules Improved speed of results Increased number of agents tested Automated systems: an overview

Welsh Gram negative panel Welsh Gram positive panel

The rationale for automated systems More reliable AST results Improved ID linked to AST Embedded expert rules Improved speed of results Increased number of agents tested Laboratory workflow Staff skill mix Epidemiological software Automated systems: an overview

Available systems MicroScan WalkAway Biomerieux Vitek 2 BD Phoenix

MicroScan 96 well plates AST based on conventional microbroth dilution MIC ID currently biochemical

Microscan Conventional panels Rapid panels Synergies plus panels Enterobacteriaceae, gram-negative non-fermenters, staphylococci, enterococci Combo, MIC-only, ID-only Rapid panels 2 - 2.5 hour ID (pre-formed enzymes) AST for Gram negative organisms (MIC > 4 hrs) Synergies plus panels Broth microdilution “Read-when-ready” MIC Resistance detection flagged in as few as 4.5 hours All results finalized in 16/18 hours Additional Yeast ID, Anaerobe ID, HNID MICroSTREP plus ® - dry format ESβL plus ® -ESβL Confirmatory Panel Panels read by WalkAway® systems autoSCAN-4 Manual

Microscan Expert rules within LabPro Alert system Pre-loaded customisable

Microscan Expert rules within LabPro Alert system Pre-loaded customisable

Vitek 2 AST based on broth susceptibility with specific cards ID currently biochemical Growth/reactions “continuously” monitored

Vitek 2 ID Cards available for AST Cards available for Gram positives Enterobacteriaceae Non-Enterobacteriaceae Neisseria/Haemophilus etc Anaerobes Yeasts AST Cards available for Gram positive cocci Gram negative bacilli Up to 22 antibiotics tested on each card

VITEK 2 – MIC Interpretation Interpretation of Raw Data Growth Parameters MIC Area Raw Data Slope % Change SLPAR 1 2 3 4 5 6 7 8 9 10 11 12 14 13 16 15 17 18 TIME (hours) 20

Vitek 2 Expert rules within the Advanced Expert System (AES) Extensive Knowledge Base >20,000 MIC distributions >2,500 Phenotypes >200 Resistance Mechanisms

Vitek 2 CARD Type Time to Result GN ID 2 to  10 hours GP ID NH ID 6 hours ANC ID YST ID 18 hours GN AST 2 to 18 Hours GP AST AST-YS01

Phoenix AST based on broth susceptibility with specific cards ID currently biochemical Growth/reactions “continuously” monitored

Phoenix AST only or Combo panels available for GN (Enterobacteriaceae/ Nonfermenters) GP (Staphylococci/ Enterococci/ Streptococci) Streptococci ID/AST

Phoenix Readings for each well taken and calculated every 20 minutes ID uses red, green, blue and UV light sources AST measures turbidity and color change Each well divided into pixels Readings taken for each pixel Entire process takes 7 minutes Pixel data analyzed for each well Readings for each well compared to previous reading and baseline Well is complete when specific amount of change is not seen Substrate/antimicrobic algorithm dependent Instrument will post results when enough data collected

Phoenix Expert rules within BDXpert based on CLSI/SFM/DIN/EUCAST rules bases

Comparison of systems

Performance ID AST Correct to genus >95% Correct to Species>90% Difficulties with difficult organisms Non-fermenters Shigella etc AST Concordant with other methods >95% Specific issues with specific drug-bug combinations & certain instruments VISA/VRSA Beta-lactams & Pseudomonas

Performance ID/AST performance relies on correct ID, correct AST plus appropriate expert interpretation Incorrect ID can lead to incorrect AST Up to 5% errors mean that results should be examined critically

Conclusions Automated systems can provide Reliable AST integrated with ID & expert rules Improved speed of results Caution about staff skill mix and interpretation of results Microscan/ Vitek 2 /Phoenix have similar performance overall Results should be examined critically