Liofilchem® Vancomycin VA Antimicrobial Susceptibility Discs, 30 µg

Liofilchem® Vancomycin Antimicrobial Susceptibility Discs are designed for determining the susceptibility of bacteria to vancomycin, a glycopeptide antibiotic effective against Gram-positive bacteria. These discs are critical tools for laboratories conducting antimicrobial susceptibility testing (AST) to guide effective clinical therapy.

Product Description

1. Active Ingredient:
   • Vancomycin, a glycopeptide antibiotic with bactericidal activity against Gram-positive organisms by inhibiting bacterial cell wall synthesis.
2. Disc Potency:
   • Available in 5 µg and 30 µg strengths to evaluate the sensitivity of various bacterial strains.
3. Application:
   • Used in Kirby-Bauer Disc Diffusion Method for AST on Mueller-Hinton agar or other suitable media.
4. Format:
   • Each disc is a paper disk impregnated with a precise amount of vancomycin, ensuring consistent performance.
5. Storage:
   • Store at 2–8°C, protected from light and moisture, in its original sealed container.

Use Cases

1. Clinical Diagnostics:
   • Detect vancomycin susceptibility in Staphylococcus aureus, including methicillin-resistant Staphylococcus aureus (MRSA).
   • Assess susceptibility of Enterococcus species, especially E. faecalis and E. faecium, which may exhibit vancomycin resistance (VRE).
2. Microbiological Research:
   • Study resistance mechanisms in Gram-positive organisms.
   • Monitor epidemiological trends of vancomycin resistance.
3. Antimicrobial Stewardship Programs:
   • Support rational antibiotic use to prevent resistance development.
   • Evaluate vancomycin effectiveness in hospital-acquired infections.

Testing Methodology

Kirby-Bauer Disc Diffusion Method

1. Preparation:
   • Use freshly prepared Mueller-Hinton Agar (MHA).
   • Adjust the bacterial inoculum to 0.5 McFarland Standard.
2. Inoculation:
   • Spread the inoculum evenly on the agar plate using a sterile swab.
3. Placement:
   • Place vancomycin discs (5 µg or 30 µg) on the inoculated plate using sterile forceps.
4. Incubation:
   • Incubate at 35 ± 1°C in ambient air for 16–20 hours.
5. Measurement:
   • Measure the diameter of the inhibition zone using a ruler or caliper.

Interpretation of Results

• Vancomycin-Resistant Enterococci (VRE) typically exhibit no zone of inhibition or zones ≤ 9 mm.
• For Staphylococcus spp., smaller zones may indicate reduced susceptibility.

Key Applications in Pathogen Detection

1. Methicillin-Resistant Staphylococcus aureus (MRSA):
   • Vancomycin is a primary treatment option for MRSA infections. Disc diffusion testing helps confirm susceptibility.
2. Vancomycin-Resistant Enterococci (VRE):
   • Screening for resistance in E. faecalis and E. faecium to guide infection control measures.
3. Other Gram-Positive Pathogens:
   • Effective for susceptibility testing of Clostridium difficile and Corynebacterium spp..

Reference Data

1. CLSI Standards:
   • Testing aligns with Clinical and Laboratory Standards Institute (CLSI) M100 guidelines for AST.
   • Standardized zones of inhibition interpretive criteria ensure reproducibility and accuracy.
2. EUCAST Guidelines:
   • European Committee on Antimicrobial Susceptibility Testing provides interpretive standards, particularly for European regions.
3. Quality Control Strains:
   • Regular testing with control strains, such as Staphylococcus aureus ATCC® 25923 and Enterococcus faecalis ATCC® 29212, ensures reliable results.

Advantages of Liofilchem® Vancomycin Discs

1. Reliability:
   • Precision in antibiotic concentration ensures reproducibility in AST.
2. Convenience:
   • Ready-to-use discs simplify laboratory workflows.
3. Global Compliance:
   • Compliant with CLSI and EUCAST standards for AST.
4. Broad Spectrum:
   • Covers a wide range of Gram-positive pathogens, including MRSA and VRE.
5. Durability:
   • Long shelf life when stored under recommended conditions.

Safety Precautions

1. Use in a well-ventilated area to minimize aerosol exposure.
2. Handle bacterial cultures and antibiotic discs following biosafety guidelines.
3. Dispose of used discs and inoculated plates in accordance with local biohazard waste regulations.

Conclusion

Liofilchem® Vancomycin Antimicrobial Susceptibility Discs (5 µg and 30 µg) are indispensable tools in clinical diagnostics, antimicrobial resistance monitoring, and stewardship programs. Their precision and reliability ensure optimal testing for vancomycin efficacy against Gram-positive bacteria.