BL-RED 25
What does the BL-RED detect?
The BL-RED assay detects beta-lactamases that hydrolyse third-generation cephalosporins (3GC), typically belonging to Ambler's class A, B and C, with the main representatives being ESBL, MBL and AmpC, respectively. Oxacillinases from Ambler's class D display variable hydrolysis profiles.
What immunoassay kits are validated with antigens?
What is beta-lactamase activity detected from?
Active beta-lactamases are detected from positive blood cultures or bacterial colonies.
From which agar plates can beta-lactamase activity be detected?
Blood Agar, MacConkey Agar, Mueller-Hinton Agar, UriSelect-4 and Chromid ESBL plates.
Which blood agar plates can be used?
Currently, the only data available are associated with Columbia horse blood (Bio-Rad) plates and, since the composition of this medium is rather standard to all other brands, then other brands should be compatible but they require validation.
Which blood cultures can be used?
Bactec Plus Aerobic/F, Bactec Plus Anaerobic/F from Becton Dickinson® and BACT/ALERT Culture Media from BioMerieux (FA Plus Aerobic, FN Plus Anaerobic).
What to do with blood cultures/agar plates from other manufacturers?
The BL-RED kit must be carried out on freshly-grown biological material, according to good microbiological practice. This test is compatible with Mueller-Hinton, MacConkey, Chromid ESBL, UriSelect-4 and horse blood agar-type solid culture media, as well as with aerobic and anaerobic Becton Dickinson® and Biomérieux® brand blood culture flasks. We recommend using media that have been validated because a threshold of positivity has been determined specifically with the DropStat reader for each of these media. A concordance should be considered with the media of other manufacturers.
How is beta-lactamase hydrolysis activity detected?
The BL-RED test is based on the use of an electroactive substrate, comparable to a 3GC whose enzymatic hydrolysis releases a product capable of generating a current measurable by voltammetry. The intensity of such a current can be measured using screen-printed electrodes and a suitably configured reader. In the BL-RED test, the measurement of a current with a greater intensity than a threshold value reflects bacterial hydrolysis of 3GCs, responsible for a reduced sensitivity of bacteria to these antibiotics.
How many tests are included in a kit?
25 units.
How should the BL-RED tests be stored?
All kits, open and unopen, must be stored between +2°C to +8°C and cannot under any circumstances be frozen or stored at room temperature.
How do the BL-RED Kits have to be shipped?
The BL-RED Kits must be shipped refrigerated as the BL reagent should not be warmed up.
How does the agar composition influence the measurement result of the BL-RED?
Agar compounds may interfere with the electrochemical measurement.
Which common ATCC strains are required for quality control?
NCTC 13439 (Klebsiella pneumoniae – VIM-1) – NCTC 13438 (Klebsiella pneumoniae – KPC-3) - NCTC 13443 (Klebsiella pneumoniae – NDM-1) - NCTC 13476 (Escherichia coli – IMP-type). Source : https://www.culturecollections.org.uk/products/bacteria-and-mycoplasmas/antimicrobial-resistance/
What volume is required for the analysis?
20µL of the mixture incubated at 37°C for 10 minutes are required for the final analysis.
How long take a measurement?
A measurement takes less than 1 minute once the sample is dispensed on the electrode.
Can an electrode be reused for multiple measurements?
No, the electrode must be discarded after each measurement.
Can the electrode and kit be used with areader other than the DropStat?
No, the kit (reagent and electrodes) must be used only with the DropStat reader.
Can measurement results be stored on the reader?
The last three measurements are displayed on the reader by pressing the reader button again. Up to 248 measurement results are stored on the reader, which can be read out electronically on a computer using the DropView Software supplied with the reader on a USB key.
How long can the BL-RED kits be stored?
BL-RED kits are stable between +2°C to +8°C for 9 months after manufacturing. All kit must be used before the expiry date indicated on the packaging.
