Liofilchem™ MTS™ Colistin CS 0.016-256, MIC Test strips

Liofilchem™ MTS™ (MIC Test Strips) Colistin CS 0.016-256 is a quantitative tool used in clinical and research laboratories to determine the minimum inhibitory concentration (MIC) of Colistin sulfate against Gram-negative bacteria, particularly multidrug-resistant (MDR) pathogens. This versatile testing solution aids in the identification of Colistin susceptibility and resistance patterns, especially in organisms such as Acinetobacter baumannii, Klebsiella pneumoniae, and Pseudomonas aeruginosa.

Product Features

• Range: 0.016 to 256 µg/mL
• Active Ingredient: Colistin sulfate (Polymyxin E)
• Format: Gradient MIC Test Strip for quantitative results
• Organisms Tested: Designed for Gram-negative bacteria, including Enterobacterales, Pseudomonas spp., and Acinetobacter spp.
• Standards: Conforms to EUCAST and CLSI standards for MIC determination.
• Applications: Suitable for diagnostic laboratories and research facilities to evaluate the susceptibility of pathogens to Colistin.

Test Procedures

1. Preparation of Media:
   • Use Mueller-Hinton Agar (MHA) as the testing medium.
   • Ensure the agar is evenly poured and solidified to a depth of 4 mm.
2. Preparation of Inoculum:
   • Prepare a 0.5 McFarland standard bacterial suspension in sterile saline or broth from a fresh bacterial culture (16–24 hours old).
   • Use a sterile swab to inoculate the Mueller-Hinton agar evenly.
3. Application of the MTS Strip:
   • Place the Colistin MTS™ strip onto the inoculated agar plate using sterile tweezers or an applicator.
   • Ensure that the strip is in full contact with the agar surface without air bubbles beneath it.
4. Incubation:
   • Incubate the plate aerobically at 35 ± 2°C for 16–20 hours.
5. Reading Results:
   • Observe the elliptical inhibition zone where bacterial growth is suppressed.
   • Read the MIC value at the point where the ellipse intersects the MIC scale on the strip.
   • Report the MIC value as per EUCAST or CLSI breakpoints.

Interpretation of Results

The MIC results can be interpreted using EUCAST or CLSI guidelines:

Storage Conditions

• Long-term Storage: Store at -20°C to maintain the integrity of the antibiotic gradient.
• Short-term Storage: Keep at 2–8°C for up to 30 days before use.
• Avoid exposure to light and humidity to ensure accuracy.

Quality Control

The Liofilchem™ MTS™ Colistin CS 0.016-256 MIC Test Strips undergo stringent quality control checks to ensure accurate and reproducible results. Test strips are validated with standard reference strains:

Deviation from these ranges may indicate a testing error or invalid strip performance.

Comparison with Other Brands

Key Advantages

1. Wide MIC Range: The 0.016–256 µg/mL range accommodates highly resistant organisms.
2. Ease of Use: Simple application procedure with clear zone interpretation.
3. Standards Compliance: Adheres to EUCAST and CLSI guidelines, ensuring reliability.
4. Cost-Effective: Competitive pricing without compromising accuracy.

The Liofilchem™ MTS™ Colistin CS 0.016-256 MIC Test Strips are an indispensable tool for microbiological labs, offering precise and reproducible results. With their wide MIC range and compatibility with EUCAST and CLSI guidelines, these strips provide valuable data for combating Gram-negative resistance effectively. Additionally, Liofilchem™ stands out for its affordability and ease of use compared to other brands, making it a preferred choice in clinical and research environments.

Detailed Comparison

1. MTS™ Colistin CS (0.064–1024 µg/mL):

• Key Features:
  • Provides a wide MIC range for routine testing, including isolates with high-level resistance.
  • Enables determination of extremely resistant strains that exceed typical susceptibility thresholds.
• Best Suited For:
  • Routine clinical microbiology labs.
  • Testing highly resistant pathogens such as Klebsiella pneumoniae and Acinetobacter baumannii.
• Limitations:
  • Not ideal for determining MIC values close to clinical breakpoints due to the broader range.

2. MTS™ Colistin CS (0.016–256 µg/mL):

• Key Features:
  • Optimized for isolates near clinical breakpoints, improving accuracy in borderline susceptibility cases.
  • Better resolution for low- to moderate-level resistance compared to the broader range MTS™ (0.064–1024 µg/mL).
• Best Suited For:
  • Scenarios where isolates exhibit MIC values near susceptibility thresholds.
  • Laboratories needing precise differentiation between susceptible and intermediate strains.
• Limitations:
  • Less effective for highly resistant organisms with MIC values exceeding 256 µg/mL.

3. ComASP™ Colistin MIC Panel (0.25–16 µg/mL):

• Key Features:
  • Based on broth microdilution (BMD), the gold-standard for colistin susceptibility testing.
  • Narrow MIC range specifically designed to evaluate clinical breakpoints as per EUCAST.
  • Offers a robust solution for confirmatory testing in cases with ambiguous or conflicting results.
• Best Suited For:
  • Regulatory testing or research to validate resistance mechanisms.
  • Confirmatory testing in laboratories handling critical patient isolates.
• Limitations:
  • Narrow MIC range excludes testing for isolates with high-level resistance (above 16 µg/mL).
  • Requires more technical expertise compared to gradient diffusion methods.

Applications and Purpose of Each Type

Conclusion

• MTS™ Colistin CS (0.064–1024 µg/mL): Ideal for routine susceptibility testing of resistant Gram-negative bacteria, especially those with high MIC values.
• MTS™ Colistin CS (0.016–256 µg/mL): Offers improved resolution for low- and moderate-resistance strains, making it better suited for testing isolates near clinical breakpoints.
• ComASP™ Colistin MIC Panel (0.25–16 µg/mL): Designed for confirmatory resistance testing as per EUCAST gold-standard methods, particularly in cases of ambiguous or conflicting results. This method is essential for regulatory or research purposes.