Please see below for currently available Fetcroja® susceptibility testing methods – further options are currently in development.
Commercially available susceptibility testing devices
Thermo Scientific™ Sensititre™ Gram Negative EUMDROXF AST Plate1
The Gram Negative EUMDROXF AST Plate delivers results directly from broth microdilution (BMD), the gold standard phenotypic method for Antimicrobial Susceptibility Testing (AST). This plate includes Fetcroja® (cefiderocol: concentration range ≤0.03–8 mg/L)2 as well as other antibiotics that are relevant for treatment of infections caused by resistant Gram-negative infections, including: colistin, ceftolozane-tazobactam, ceftazidime-avibactam, meropenem-vaborbactam and imipenem-cilastatin-relebactam. Thermo Scientific™ CAMHB and demineralised water are recommended for use with these plates.
Kirby-Bauer disc diffusion method
Disc diffusion of Fetcroja is performed according to EUCAST standard methodology for non-fastidious organisms on regular unsupplemented Mueller-Hinton agar. It is no more complicated than disc diffusion for other cephalosporins.3 Iron-limited agar medium is NOT required for susceptibility testing of Fetcroja® by Kirby-Bauer disc diffusion method, and standard cation-adjusted Mueller-Hinton agar plates can be used.4
Liofilchem® MTS™ Cefiderocol FDC 0.016–256 μg/mL5
The MTS™ (MIC Test Strip) Cefiderocol FDC 0.016–256 μg/mL is a quantitative method for the in vitro susceptibility testing of Pseudomonas aeruginosa to Fetcroja®. Cefiderocol MTS™ consists of special porous paper impregnated with a pre-defined concentration gradient of Fetcroja®, from 0.016 to 256 μg/mL, used to determine the MIC against bacteria as tested on Mueller-Hinton agar media using overnight incubation and manual reading procedures. Liofilchem® or Becton Dickinson standard Mueller-Hinton agar plates are recommended for use with these test strips.
Bruker UMIC® Cefiderocol6
UMIC® Cefiderocol delivers results directly from broth microdilution in full compliance with the EUCAST and CLSI standards and can conveniently be used alongside other UMIC® testing devices. UMIC® Cefiderocol is suitable for quantitative MIC determination of Fetcroja® (cefiderocol: concentration range 0.03–32 μg/mL) against Enterobacterales, P. aeruginosa, A. baumannii and S. maltophilia. This testing method requires iron-depleted CAMHB (sold separately), but does not require any additional equipment.
Liofilchem® ComASP® Cefiderocol 0.008–1287
ComASP® Cefiderocol 0.008–128 is a compact, less time-consuming version of the broth microdilution reference method, which allows AST for Fetcroja® to be performed as recommended by international standards (i.e. CLSI, EUCAST, ISO). ComASP® is a two-test panel containing dried cefiderocol in 15 two-fold dilutions (cefiderocol: concentration range 0.008–128 μg/mL). ComASP® is used for the quantitative MIC determination of Fetcroja against Enterobacterales, P. aeruginosa, A. baumannii and S. maltophilia. These plates require iron-depleted CAMHB, vials of which are included in each kit.
|
Thermo ScientificTM SensititreTM plate
|
Cefiderocol (FDC) Kirby–Bauer disc |
LIOFILCHEM® MTSTM
|
|---|---|---|
 |
 |
 |
|
BRUKER UMIC® CEFIDEROCOL
|
Liofilchem® ComASP® Cefiderocol 0.008–128
|
|
 |
 |
|
Description |
Status
|
Pack Size
|
Catalogue Number
|
Supplier
|
|---|---|---|---|---|
| Sensititre™ Gram Negative EUMDROXF AST Plate |
IVD
|
10 plates
|
EUMDROXF
|
Visit:
|
|
Cefiderocol (FDC) KB Discs 30 μg
|
CE-marked/IVD
|
50 discs
250 discs
|
9266/1
9266
|
Visit:
|
|
Cefiderocol 30 μg Cartridge Discs
|
CE-marked/IVD
|
250 discs
|
FDC30C
|
Visit:
|
|
Cefiderocol Antimicrobial Susceptibility Discs
|
CE-marked/IVD
|
250 discs
|
CT1964B
|
Visit:
|
|
MTS™ Cefiderocol 0.016–256
|
IVD
|
10 strips
30 strips
100 strips
|
920671
92067
920670
|
Visit:
|
|
UMIC® Cefiderocol
|
CE-marked/IVD
|
40 tests |
UM-CID-040
|
Visit:
|
|
ComASP® Cefiderocol 0.008–128
|
CE-marked/IVD
|
4 x 2 (8) tests
|
75009
|
Visit:
|
AST, antimicrobial susceptibility testing; CAMHB, cation-adjusted Mueller-Hinton broth; EUCAST, European Committee on Antimicrobial Susceptibility Testing; IVD, in vitro diagnostic.
Interpretative criteria and quality control ranges
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ORGANISM
|
EUCAST MIC BREAKPOINT (≤S>R)
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EUCAST ZONE DIAMETER BREAKPOINT (≥S<R)
|
ATU
|
|---|---|---|---|
|
Enterobacterales
|
2 mg/L
|
22 mm
|
18-22 mm‡
|
|
Pseudomonas aeruginosa
|
2 mg/L
|
22 mm
|
14-22 mm‡
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|
Acinetobacter baumannii*
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PK-PD breakpoint
(2 mg/L)
|
≥17 mm**
|
N/A
|
|
Stenotrophomonas maltophilia*
|
PK-PD breakpoint
(2 mg/L)
|
≥20 mm†
|
N/A
|
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QC STRAIN
|
MICRODILUTION QC RANGE
|
ZONE DIAMETER QC RANGE
|
|---|---|---|
|
Escherichia coli ATCC 25922
|
0.06–0.5 mg/L, target 0.125–0.25 mg/L
|
24–30 mm, target 27 mm
|
|
Pseudomonas aeruginosa ATCC 27853
|
0.06–0.5 mg/L, target 0.125–0.25 mg/L
|
23–29 mm, target 26 mm
|
Adapted from EUCAST.8,9
*There is insufficient evidence that the organism or group is a good target for therapy with the agent. An MIC with a comment but without an accompanying S, I (susceptible, increased exposure) or R categorisation may be reported. **Zone diameters of ≥17 mm for the cefiderocol 30 μg disk correspond to MIC values below the PK-PD breakpoint of S ≤2 mg/L. †Zone diameters of ≥20 mm for the cefiderocol 30 μg disk correspond to MIC values below the PK-PD breakpoint of S ≤2 mg/L.5 ‡Isolates with zones falling within the ATU should be retested, ideally using a method providing an MIC, as some susceptible isolates may have zone diameters <22 mm.
ATU, area of technical uncertainty; EUCAST, European Committee on Antimicrobial Susceptibility Testing; MIC, minimum inhibitory concentration; N/A, not applicable; PD, pharmacodynamics; PK, pharmacokinetics; QC, quality control; R, resistant; S, susceptible.
Fetcroja® susceptibility testing materials
Testing materials for research use only
Thermo Scientific™ Custom Sensititre™ Plates10
- Custom dried plates
- Custom frozen plates (containing iron-depleted CAMHB)
For Pseudomonas aeruginosa only:
- bioMérieux ETEST® strip
Summary table of Fetcroja® susceptibility testing materials
|
DESCRIPTION
|
SUPPLIER
|
STATUS
|
CATALOGUE #
|
COMMENT
|
|---|---|---|---|---|
|
30 µg FDC KB Disc
|
Liofilchem®
|
IVD
|
9266/1
9266 |
50 discs
5 x 50 discs (250 discs) |
|
30 µg FDC KB Disc
|
Mast Group Ltd
|
IVD
|
FDC30C
|
5 x 50 discs
(250 discs) |
|
30 µg FDC KB Disc
|
ThermoFisher Scientific
|
IVD
|
CT1964B
|
250 discs |
|
MTS™ Cefiderocol 0.016–256
|
Liofilchem® | IVD | 920671 92067 920670 |
Pseudomonas aeruginosa only |
|
Sensititre™ Gram Negative EUMDROXF AST Plate
|
ThermoFisher Scientific
|
IVD
|
EUMDROXF
|
10 plates |
|
ETEST® strip
|
bioMérieux
|
IVD
|
TBC
|
Pseudomonas
aeruginosa only |
|
UMIC® Cefiderocol |
Bruker
|
IVD
|
UM-CID-040
|
40 tests
|
|
ComASP® Cefiderocol 0.008–1281
|
Liofilchem®
|
IVD
|
75009
|
4 x 2 (8) tests
Kit includes iron-depleted CAMHB |
|
Sensititre™ custom
frozen plate |
ThermoFisher Scientific
|
RUO
|
FROZENPLATE
|
10 plates
Contains iron-depleted CAMHB< |
|
Sensititre™ custom
dried plate |
ThermoFisher Scientific
|
RUO
|
DRIEDPLATE
|
10 plates
|
CAMHB, cation-adjusted Mueller-Hinton broth; IVD, in vitro diagnostic; KB, Kirby-Bauer; RUO, research use only.
HOW DOES THIS SUPPORT THE NICE RECOMMENDATION FOR USE OF FETCROJA® IN ENGLAND?
Cefiderocol is recommended, within its marketing authorisation, as an option for treating severe drug-resistant infections caused by aerobic Gram-negative bacteria.11
The decision to offer cefiderocol should be guided by results from tests for microbiological susceptibility and mechanisms of resistance that confirm that the infection is susceptible to cefiderocol, and not susceptible to other suitable antibiotics.11
Prescribers should follow the recommendations on new antimicrobials in the NICE guideline on antimicrobial stewardship.
References:
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Sensititre™ Gram Negative EUMDROXF AST Plate. Available at: https://www.thermofisher.com/order/catalog/product/EUMDROXF#/EUMDROXF. Accessed January 2023.
- Kresken M, et al. In vitro activity of cefiderocol against aerobic Gram-negative bacterial pathogens from Germany. Antimicrob Agents. 2020;56(4):106128.
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Breakpoints for cefiderocol from EUCAST. Addendum (May 2020) to EUCAST breakpoint tables v10.0. Breakpoints to be included in EUCAST breakpoint tables v11.0. Available at: https://www.eucast.org/fileadmin/src/media/PDFs/EUCAST_files/Breakpoint_tables/Addenda/Cefiderocol_addendum_20200501.pdf. Accessed January 2023.
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Liofilchem®. MTS™ Cefiderocol 0.016-256. Available at: https://www.liofilchem.com/images/brochure/mic_test_strip_patent/MTS51.pdf. Accessed January 2023.
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Matuscheck E, et al. Cefiderocol: EUCAST criteria for disc diffusion and broth microdilution for antimicrobial susceptibility testing. J Antimicrob Chemother. 2022,77:1662–1669.
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Bruker. UMIC® Cefiderocol, IVD-CE (Flyer). Available at: https://www.bruker.com/en/products-and-solutions/microbiology-and-diagnostics/antimicrobial-susceptibility-testing/umic.html. Accessed January 2023.
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Liofilchem®. ComASP® Cefiderocol 0.008–128. Available at: http://www.liofilchem.net/login/pd/pi/75009_PI.pdf. Accessed January 2023.
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The European Committee on Antimicrobial Susceptibility Testing. Breakpoint tables for interpretation of MICs and zone diameters. Version 12.0, 2022. Available at: https://www.eucast.org/fileadmin/src/media/PDFs/EUCAST_files/Breakpoint_tables/v_12.0_Breakpoint_Tables.pdf. Accessed January 2023.
- The European Committee on Antimicrobial Susceptibility Testing. Routine and extended internal quality control for MIC determination and disk diffusion as recommended by EUCAST. Version 11.0, 2021. Available at: https://www.eucast.org/fileadmin/src/media/PDFs/EUCAST_files/QC/v_11.0_EUCAST_QC_tables_routine_and_extended_QC_pdf.pdf. Accessed January 2023.
-
Thermo Fisher Scientific. SensititreTM Custom Plate: RUO MIC or BP Not including Yeast or Mycobacterium. Available at: https://www.thermofisher.com/order/catalog/product/DRIEDPLATE#/DRIEDPLATE. Accessed January 2023.
- NICE. Cefiderocol for treating severe drug-resistant gram-negative bacterial infections, August 2022. Available at: https://www.nice.org.uk/about/what-we-do/life-sciences/scientific-advice/models-for-the-evaluation-and-purchase-of-antimicrobials/cefiderocol. Accessed January 2023.