evaluación del sistema de identificación y sensibilidad bd
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Evaluación del sistema de identificación y
sensibilidad BD Phoenix de acuerdo al
standard EUCAST
EUCAST: Qué, por qué, cómo y cuándo: las claves del éxito
Malaga, 2 de junio, 2010
Departamento de Microbiología IIUniversidad Complutense. Madrid
Hospital Universitario Ramón y CajalSERVICIO DE MICROBIOLOGÍA Y PARASITOLOGÍA
Dr. Rafael Cantón
1920 1930 1940 1950 1960 1970 1980 1990 2000
Discover of antimicrobial agents
Introduction ofantibiotic in therapeutics
Normalization of in vitro
susceptibility testing
Interpretivecriteria
Description ofresistance
mechanisms
Relation between resistance and clinical failure
Interpretive reading of the antibiograms
AutomationThe antimicrobial susceptibilitytesting process…
Cantón R. Enf Inf Microbiol Clin 2002; 20:176-85
MIC based automatic systems MIC based automatic systems
Main objectives
To produce antimicrobial susceptibility testing (AST) resultsin a mechanized mode
To standardize AST avoiding uncontrolled differences
To offer AST in a shorter period of time than manual methods
To interpret AST results (clinical categorization / interpretation)
Antimicrobial susceptibility automatic systemsAntimicrobial susceptibility automatic systems
Now with EUCAST breakpoints!
Antimicrobial susceptibility automatic systemsAntimicrobial susceptibility automatic systems
MIC based systems
Device Inoculation ReadingReporting time (hours)
Sensititre Manual orsemiautomatic
Manual read orfluorescence
18-24
MicroScan Manual Turbidity and fluorometer
15-183.5-7
Phoenix Manual orSemiautomatic
Turbidity andcolorimetric
4-16
Vitek2 Semiautomatic Fluorometer,photometer
4-18
Data obtained from Evangelista & Truant. In: Commercial methods in Clinical Microbiology. 2002
Issues with EUCAST breakpoint implementation
Lower ranges of concentrations
are needed (EUCAST breakpointsare mostly lower than CLSI)
-
instability of certain antibiotics might affect accuracy (essentialand categorical agreements)
-
carbapenems, β-lactam-β-lactamase inhibitor combinations, …
-
major discrepancies (false resistance) could be observed, particularlywith isolates expressing low level resistance mechanisms
Antimicrobial susceptibility automatic systemsAntimicrobial susceptibility automatic systems
Issues with EUCAST breakpoints implementation
S and R breakpoints can be ...
-
too close (essential and categorical agreements can be affected)
i.e. ciprofloxacin and enterobacteriaceae (S≤
0.5 / R >1)
vancomycin and staphylococci (S≤
2 / R >2)
-
too separate (a higher concentration range is needed in the panel)
i.e. aztreonam and P. aeruginosa (S≤
1 / R >16)*
*The R breakpoint was increased from 8 to 16 mg/L to avoid dividing thewild type MIC distribution. The R breakpoint relates to high dose therapy.The S breakpoint is set to ensure that wild type isolates are reported I.
Antimicrobial susceptibility and automatic systemsAntimicrobial susceptibility and automatic systems
www.eucast.org
Low level resistance or decreased susceptibility
High level resistanceRS
ECOFF
RS
Issues with EUCAST breakpoint implementation
A desirable attribute...
... to include drug concentrations below or equal to ECOFFs*allowing detection of wild type organisms (no-R mechanism)
*epidemiological cut off values
A philosophical and technical change...
... breakpoints are differently expressed
S R
EUCAST ≤ >
CLSI ≤ ≥
Antimicrobial susceptibility and automatic systemsAntimicrobial susceptibility and automatic systems
www.eucast.org
www.eucast.org
www.eucast.org
www.eucast.org
Antimicrobial susceptibility automatic systemsAntimicrobial susceptibility automatic systems
MIC based systems
Device Inoculation ReadingReporting time (hours)
Sensititre Manual orsemiautomatic
Manual read orFluorescence
18-24
MicroScan Manual Turbidity and fluorometer
15-183.5-7
Phoenix Manual orSemiautomatic
Turbidity andcolorimetric
4-16
Vitek2 Semiautomatic Fluorometer,photometer
4-18
Data obtained from Evangelista & Truant. In: Commercial methods in Clinical Microbiology. 2002
These system fulfill FDA and ISO accuracy performance
Acceptable performance for the clinical data for automatic ASTdevices with reference method (FDA)
Essential agreement (±
1 dilution):
>89.9%
Category agreement (interpretive results, SIR) >89.9%
Major discrepancies (false resistance): ≤
3%* *based on the no. of susceptible organisms tested
Very major discrepancies (false susceptibility): ≤
1.5%****based on the no. of resistant organisms tested
Growth failure rates: < 10%***
***for any genus or species tested
Antimicrobial susceptibility automatic systemsAntimicrobial susceptibility automatic systems
Antimicrobial Susceptibility Test (AST) Systems. Guidance for Industry and FDA Class II Special Controls Guidance Document:, August 28, 2009
http://www.fda.gov/MedicalDevices/DeviceRegulationandGuidance/GuidanceDocuments/ucm080564.htm
Accuracy of automatic AST devices (ISO 20776-2:2007)
Data shall be analyzed by using the appropriate interpretive breakpoints
Essential agreement (±
1 dilution):
≥
90%
Category agreement (interpretive results, SIR) ≥
90%
Major discrepancies (false resistance): ≤
3%* *based on the no. of susceptible organisms tested
Very major discrepancies (false susceptibility): ≤
3%****based on the no. of resistant organisms tested
Reproducibility
(±
1 dilution and/or SIR results): ≥
95%
***for any genus or species tested
Antimicrobial susceptibility automatic systemsAntimicrobial susceptibility automatic systems
Clinical laboratory testing and in vitro diagnostic test systems
-
Susceptibility testing of infectious agents and evaluation of performance of antimicrobial susceptibility test devices -
Part 2: Evaluation of performance of antimicrobial susceptibility test devices. International Standard ISO 20776-2:2007, ISO, Geneva.
Assessment of the PHOENIX system and EUCAST breakpoints for Assessment of the PHOENIX system and EUCAST breakpoints for antimicrobial susceptibility testing against contemporary isolatantimicrobial susceptibility testing against contemporary isolates es
expressing relevant resistance mechanismsexpressing relevant resistance mechanisms
MI Morosini, M García-Castillo, R Cantón, Vienna, 20th ECCMID, 2010
Objective:-
To evaluate the accuracy of the PHOENIX system using EUCAST
criteria
PHOENIX system: UNMIC/ID-62 Gram negative panelsPMIC/ID-53 Gram positive panels
Comparator: routine or historical data obtained using CLSI guidelinesdiscrepant results resolved using Etest
Bacterial isolates:-
150 fresh consecutive isolates (51 Enterobacteriaceae, 40 P. aeruginosa;
30 S. aureus, 20 Enterococcus spp.)-
93 stored isolated with well characterized resistance mechanisms
-
96 ESBL and 50 MBL producing Enterobacteriaceae-
10 MLB producing P. aeruginosa
- 20 MRSA,
17 VRE
Essential agreement: results within ±
1 log2
dilution
Error rates: -
Minor error 1) the comparator/reference result is resistant (R) or
susceptible (S) and the test result is intermediate (I)2) the comparator/reference result is I and the test device
result is S or R
-
Major error the comparator/reference result is S and the test device is R
-
Very major error the comparator/reference result is R and the testdevice is S
Categorical agreement, concordance between two data set in theclassification of an isolate in SIR category regarding a specific antibiotic
Assessment of the PHOENIX system and EUCAST breakpoints for Assessment of the PHOENIX system and EUCAST breakpoints for antimicrobial susceptibility testing against contemporary isolatantimicrobial susceptibility testing against contemporary isolates es
expressing relevant resistance mechanismsexpressing relevant resistance mechanismsMI Morosini, M García-Castillo, R Cantón
Hospital Universitario Ramón y Cajal. Madrid. Vienna, 20th ECCMID, 2010
Fresh isolates(n=150)
Isolates with known resistance phenotypes
(n=193)
Categorical agreement 96.0% 95.5%
Interpretive discrepancies
-
minor discrepancies 0,8% 3,4%
-
Major discrepancies 0,6% 1,9%
-
Very major discrepancies 2,3% 0,8%
Assessment of the PHOENIX system and EUCAST breakpoints for Assessment of the PHOENIX system and EUCAST breakpoints for antimicrobial susceptibility testing against contemporary isolatantimicrobial susceptibility testing against contemporary isolates es
expressing relevant resistance mechanismsexpressing relevant resistance mechanismsMI Morosini, M García-Castillo, R Cantón
Hospital Universitario Ramón y Cajal. Madrid. Vienna, 20th ECCMID, 2010
Assessment of the PHOENIX system and EUCAST breakpoints for Assessment of the PHOENIX system and EUCAST breakpoints for antimicrobial susceptibility testing against contemporary isolatantimicrobial susceptibility testing against contemporary isolates es
expressing relevant resistance mechanismsexpressing relevant resistance mechanismsMI Morosini, M García-Castillo, R Cantón
Hospital Universitario Ramón y Cajal. Madrid. Vienna, 20th ECCMID, 2010
Grupo Total test
categorical agreement
(%)
Minor(%)
Major(%)
VeryMajor (%)
Essential agreement
(%)Enterobacteriaceae 1970 92.8 5,2 1,3 0,6 95,4
P. aeruginosa 480 95,4 1,5 0,4 2,7 97,3
S. aureus 340 98,8 0,9 0 0,3 97,6
Enterococcus spp. 229 97,4 0,4 0,4 1,7 94,7
Assessment of the PHOENIX system and EUCAST breakpoints for Assessment of the PHOENIX system and EUCAST breakpoints for antimicrobial susceptibility testing against contemporary isolatantimicrobial susceptibility testing against contemporary isolates es
expressing relevant resistance mechanismsexpressing relevant resistance mechanismsMI Morosini, M García-Castillo, R Cantón
Hospital Universitario Ramón y Cajal. Madrid. Vienna, 20th ECCMID, 2010
AgentMIC distribution (Phoenix) No. of error rates
>-2 -2 -1 0 1 2 >+2 Minor Major Very MajorAMC 2 3 3 51 24 13 17 7PTZ 96CTX 8 2 82 4 3CAZ 3 2 7 67 15 1 1 16 1IMI 12 83 1 1
MER 2 93 1 1CIP 2 5 1 75 8 5 9GEN 1 1 94 2TOB 96SXT 2 1 92 1 1
ESBL-producingEnterobacteriaceae(n=96)
Assessment of the PHOENIX system and EUCAST breakpoints for Assessment of the PHOENIX system and EUCAST breakpoints for antimicrobial susceptibility testing against contemporary isolatantimicrobial susceptibility testing against contemporary isolates es
expressing relevant resistance mechanismsexpressing relevant resistance mechanismsMI Morosini, M García-Castillo, R Cantón
Hospital Universitario Ramón y Cajal. Madrid. Vienna, 20th ECCMID, 2010
AgentMIC distribution (Phoenix) No. of error rates
>-2 -2 -1 0 1 2 >+2 Minor Major Very MajorAMC 50PTZ 48 2CTX 50CAZ 50IMI 5 15 19 4 7 13
MER 6 3 3 31 4 3 15CIP 5 2 8 34 1 14 1GEN 1 10 37 1 1TOB 2 1 8 38 1 11 1SXT 1 2 47
Carbapenemase producingEnterobacteriaceae(n=50)
Antimicrobial susceptibility and automatic systemsAntimicrobial susceptibility and automatic systems
assessment of the Phoenix system & EUCAST breakpoints
Madrid*(393 isolates)
Siena**(362 isolates)
Essential agreement (±1 log2
) 96.0% 99.1%
Categorical agreement (S/I/R) 95.8% 96.2%
Interpretive discrepancies
-
minor discrepancies 2.4% 2.8%
-
Major discrepancies 1.2% 0.8%
-
Very major discrepancies 1.1% 1.3%
*Morosini, García-Castillo, Cantón. Ramón y Cajal University Hospital. Madrid (Spain)**Giani, Conte, D’Andrea, Rossoloni. University of Siena (Italy)
Posters presented at 20th ECCMID, 2010
Antimicrobial susceptibility and automatic systemsAntimicrobial susceptibility and automatic systems
Concluding remarks
Automatic antimicrobial susceptibility testing systems are part ofclinical microbiology laboratories
Automatic systems available in Europe have incorporated the EUCAST breakpoints,
At present, Phoenix system is one of the system that moreadequately accomplish the EUCAST criteria
Evaluation of Phoenix system in two different European countriesshows that :
-
this system fulfill FDA and ISO accuracy performance requirements-
discrepant results might appear in isolates with enzymatic/heteroresistance mechanisms
Do your best... but better with EUCAST
Antimicrobial susceptibility and automatic systemsAntimicrobial susceptibility and automatic systems
Evaluación del sistema de identificación y
sensibilidad BD Phoenix de acuerdo al
standard EUCAST
EUCAST: Qué, por qué, cómo y cuándo: las claves del éxito
Malaga, 2 de junio, 2010
Departamento de Microbiología IIUniversidad Complutense. Madrid
Hospital Universitario Ramón y CajalSERVICIO DE MICROBIOLOGÍA Y PARASITOLOGÍA
Dr. Rafael Cantón