Liofilchem™ MULTODISCS

Liofilchem® MULTODISCS are innovative antibiotic susceptibility testing tools designed as rings with eight arms, each ending in a 6 mm antibiotic-impregnated disc. Each disc is clearly marked with an identification code, and an inert material barrier at the end of each arm ensures precise circular diffusion and easily measurable inhibition zones. MULTODISCS are highly effective for the Kirby-Bauer disk diffusion method (KB testing), offering a broad range of configurations to meet various diagnostic needs.

Features:

1. High-Quality Materials:
   • Manufactured from premium absorbent paper in compliance with WHO and FDA specifications.
   • Antibiotic potency adheres to DIN specifications, ensuring the concentration of each antibiotic is within 90-125% of the stated value.
2. Innovative Design:
   • Eight antibiotics per ring, with equidistant placement for homogeneous diffusion.
   • Barrier at the disc arm ends prevents diffusion along the arm, guaranteeing accurate inhibition zone formation.
3. Comprehensive Testing:
   • Suitable for various bacterial and fungal species, ensuring reliable susceptibility testing.

Contents:

• Each pack includes 100 rings stored in a jar with a desiccant to maintain dryness and an instruction leaflet.

Method Principle:

MULTODISCS are applied to the surface of an agar medium inoculated with a broth culture prepared from pure colonies. After incubation, inhibition zones around each disc are measured and compared to standardized reference diameters, categorizing microorganisms as sensitive, intermediate, or resistant to the tested antibiotics.

Applications:

• Ideal for routine clinical susceptibility testing in medical laboratories.
• Effective for testing Enterobacteria, Enterococci, Pseudomonas, Staphylococci, Streptococci, Acinetobacter, and yeasts.

Testing Procedure:

1. Preparation:
   • Remove the jar from refrigeration and allow it to equilibrate to room temperature (~1 hour) to prevent condensation on the discs.
2. Inoculation:
   • Suspend 4-5 well-isolated colonies in 5 mL of Tryptic Soy Broth or a similar culture medium.
   • Incubate until a turbidity equivalent to 0.5 McFarland standard is achieved.
3. Plate Preparation:
   • Swab the inoculum onto the agar plate to ensure uniform bacterial growth.
4. Placement:
   • Within 15 minutes of inoculating the plate, press the MULTODISC onto the agar surface using sterile forceps.
5. Incubation:
   • Incubate plates as per the growth requirements of the microorganism under examination (e.g., 36 ± 1°C for 18-24 hours).

Evaluation of Results:

• Measure inhibition zones and interpret them using CLSI or EUCAST standards.
• Results provide critical insights into microbial sensitivity or resistance to specific antibiotics.

Quality Control:

Each batch is tested for quality using reference strains, such as:

• Enterococcus faecalis ATCC® 29212
• Escherichia coli ATCC® 25922
• Pseudomonas aeruginosa ATCC® 27853
• Staphylococcus aureus ATCC® 25923

Limitations:

• As an in vitro technique, diffusion antibiograms do not replicate in vivo conditions.
• Results may vary due to factors like culture medium quality, incubation conditions, and disc placement.

Storage:

• Long-term storage: -20°C in the original packaging.
• Short-term storage: 2-8°C, ensuring the discs are kept dry and protected from heat and temperature fluctuations.

Precautions:

• For in vitro diagnostic use by trained professionals only.
• Handle with aseptic techniques and adhere to laboratory safety protocols.

Ordering Information:

The primary differences between Liofilchem’s Multodisc Enterobacteria 1 and Multodisc Enterobacteria 2 lie in the antibiotics included and their specific applications for Enterobacteria testing. Below is a comparison of the two Multodisc products:

Multodisc Enterobacteria 1

Ref: 95220

Purpose: Used for broad susceptibility testing of Enterobacteria species.

Antibiotics Included and Potency:

1. Amikacin (AK): 30 µg
2. Aztreonam (ATM): 30 µg
3. Piperacillin-Tazobactam (TZP): 36 µg
4. Chloramphenicol (C): 30 µg
5. Trimethoprim-Sulfamethoxazole (SXT): 25 µg
6. Netilmicin (NET): 10 µg
7. Cefotaxime (CTX): 5 µg
8. Nitrofurantoin (F): 100 µg

Multodisc Enterobacteria 2

Ref: 95240

Purpose: Focused on additional susceptibility testing for Enterobacteria, including combinations targeting resistance mechanisms.

Antibiotics Included and Potency:

1. Levofloxacin (LEV): 5 µg
2. Cefoxitin (FOX): 30 µg
3. Piperacillin-Tazobactam (TZP): 36 µg
4. Cefuroxime (CXM): 30 µg
5. Streptomycin (S): 300 µg
6. Netilmicin (NET): 10 µg
7. Ampicillin-Sulbactam (AMS): 20 µg
8. Tobramycin (TOB): 10 µg

Key Differences

1. Antibiotics Tested:
   • Enterobacteria 1 includes Amikacin (AK), Aztreonam (ATM), Cefotaxime (CTX), and Nitrofurantoin (F), which are absent in Enterobacteria 2.
   • Enterobacteria 2 includes Levofloxacin (LEV), Cefoxitin (FOX), Cefuroxime (CXM), Ampicillin-Sulbactam (AMS), Streptomycin (S), and Tobramycin (TOB), which are absent in Enterobacteria 1.
2. Focus on Resistance Mechanisms:
   • Enterobacteria 1 covers a broader spectrum of first-line and commonly used antibiotics.
   • Enterobacteria 2 includes antibiotics targeting specific resistance mechanisms (e.g., Ampicillin-Sulbactam for beta-lactamase producing strains, Cefoxitin for ESBL detection, etc.).
3. Clinical Relevance:
   • Enterobacteria 1 is ideal for initial testing and common Enterobacteria infections.
   • Enterobacteria 2 is better suited for resistance studies and more advanced susceptibility profiling.
4. Potency Differences:
   • Streptomycin (300 µg) and combinations like Ampicillin-Sulbactam are unique to Enterobacteria 2, targeting resistant pathogens.

By using both Multodiscs, clinicians and microbiologists can comprehensively assess Enterobacteria susceptibility to a wide array of antibiotics, addressing both first-line therapies and resistance mechanisms.

References:

1. CLSI Standards M02, M100, M44, and M60.
2. EUCAST breakpoint tables for MICs and zone diameters.
3. WHO and FDA technical guidelines.