Liofilchem ESBL disc kit (acc. to CLSI) 50 tests

The Liofilchem™ ESBL Disc Kit is designed for the confirmation of Extended-Spectrum Beta-Lactamase (ESBL)-producing Enterobacteriaceae. ESBLs hydrolyze most penicillins and cephalosporins, including oxyimino-beta-lactams, but are inhibited by beta-lactamase inhibitors such as clavulanic acid. This kit utilizes the Combination Disc Test (CDT) method to differentiate ESBL-producing isolates from those resistant due to other mechanisms. The test follows CLSI (Clinical and Laboratory Standards Institute) guidelines.

Key Features

1. Highly Accurate Detection:
   • Detects ESBL activity in Enterobacteriaceae using synergy between cephalosporins and clavulanic acid.
2. Validated for Clinically Relevant Strains:
   • Effective for Escherichia coli, Klebsiella pneumoniae, Klebsiella oxytoca, and Proteus mirabilis.
3. Compliant with CLSI Guidelines:
   • Ensures reliable and standardized ESBL confirmation testing.
4. Convenient Packaging:
   • Contains 4 x 50 discs, each individually packaged in a blister with a desiccant for optimal storage.

Kit Contents

• 4 x 50 discs cartridges:
  • CTX 30 μg: Cefotaxime.
  • CTL 30+10 μg: Cefotaxime + Clavulanic Acid.
  • CAZ 30 μg: Ceftazidime.
  • CAL 30+10 μg: Ceftazidime + Clavulanic Acid.

Method Principle

• Combination Disc Test (CDT):
  • Compares the inhibition zones of cephalosporins alone (Cefotaxime or Ceftazidime) and in combination with Clavulanic Acid.
  • A ≥ 5 mm increase in inhibition zone diameter with clavulanic acid indicates a positive ESBL result.

Test Procedure

1. Prepare the Test Organism:
   • Use a fresh, pure culture to prepare a suspension equivalent to 0.5 McFarland Standard.
2. Inoculate the Agar Plate:
   • Spread the suspension evenly over a Mueller Hinton Agar plate using a sterile swab.
3. Apply the Discs:
   • Place the discs (CTX, CTL, CAZ, and CAL) onto the plate, ensuring adequate spacing.
4. Incubation:
   • Incubate at 35 ± 2°C for 18-24 hours.
5. Interpret Results:
   • Measure the inhibition zones and compare as per the following table:

Interpretation of Results

• ZCAL = Zone around CAL disc.
• ZCAZ = Zone around CAZ disc.
• ZCTL = Zone around CTL disc.
• ZCTX = Zone around CTX disc.

Quality Control

Storage and Shelf Life

• Storage:
  • Unopened blister: -20°C to +8°C.
  • Opened cartridges: 2-8°C for up to 7 days.
• Shelf Life: Valid until the expiry date indicated on the packaging.

Advantages

• Highly Reliable: Distinguishes ESBL-producing bacteria from those resistant due to other mechanisms.
• Standardized: Follows CLSI M100-S24 guidelines for ESBL detection.
• Easy to Use: Ready-to-use discs simplify laboratory workflows.
• Broad Applicability: Validated for major Enterobacteriaceae, including E. coli and K. pneumoniae.

Warnings and Precautions

1. For in vitro diagnostic use (IVD) only.
2. Handle all microbiological materials as potentially infectious.
3. Follow standard laboratory safety and aseptic techniques.
4. Dispose of used discs according to laboratory waste protocols.

Limitations

• Results from diffusion susceptibility tests are in vitro and cannot replicate complex in vivo conditions.
• Variables such as medium quality, incubation conditions, and inoculum size may influence results.

Packaging

References

1. CLSI M100-S24 - Performance Standards for Antimicrobial Susceptibility Testing; 2014.
2. FDA-BAM: Antimicrobial Susceptibility Testing.
3. ISO 20776-1: 2019 - Methods for antimicrobial susceptibility testing.

Why Choose Liofilchem ESBL Disc Kit?

• Validated for ESBL Detection: Provides accurate and reliable confirmation of ESBL-producing Enterobacteriaceae.
• Compliant with CLSI Standards: Trusted for clinical microbiology and infection control applications.
• User-Friendly: Simplifies the process of ESBL confirmation with pre-packaged discs.