Antibiotic Susceptibility Testing (AST), MICs & Antibiogram Analysis at Envirocare Laboratory

Antimicrobial resistance continues to present major challenges across clinical, veterinary, food production, and environmental sectors. Accurate Antibiotic Susceptibility Testing (AST) and Minimum Inhibitory Concentration (MIC) analysis are essential tools for understanding microbial resistance patterns and supporting informed treatment, product development, and food safety decisions.

At Envirocare Laboratory, we provide advanced AST, MIC, and Antibiogram Analysis services under an ISO/IEC 17025-accredited quality system. Our methodologies are aligned with internationally recognised CLSI and EUCAST standards, ensuring technically sound, traceable, and reliable results.

What is Antibiotic Susceptibility Testing (AST)?

Antibiotic Susceptibility Testing (AST) is used to determine how susceptible or resistant a microorganism is to specific antimicrobial agents. AST helps identify effective antimicrobial options and supports resistance monitoring programmes.

At Envirocare Laboratory, AST is performed using validated methodologies under controlled laboratory conditions. Our testing supports applications in:

  • Clinical microbiology
  • Veterinary diagnostics
  • Food safety investigations
  • Environmental monitoring
  • Pharmaceutical and product development

Our approach focuses on quality, traceability, and internationally accepted best practices.

Understanding Minimum Inhibitory Concentrations (MICs)

Minimum Inhibitory Concentration (MIC) testing determines the lowest concentration of an antimicrobial agent required to inhibit visible microbial growth under defined conditions.

MIC testing provides more detailed antimicrobial performance information and is widely used for:

  • Antimicrobial effectiveness evaluation
  • Product development studies
  • Comparative analysis
  • Resistance trend investigations
  • Research and validation work

All MIC determinations at Envirocare Laboratory are:

  • Performed using standardised validated methodologies
  • Traditional or Spectrophotometric methods
  • Verified using appropriate control and reference strains
  • Supported by calibrated equipment and traceable reagents

MIC₅₀ and MIC₉₀ Indicators

MIC data often includes important statistical indicators such as:

  • MIC₅₀ – the concentration inhibiting 50% of isolates
  • MIC₉₀ – the concentration inhibiting 90% of isolates

These indicators assist in evaluating antimicrobial performance across microbial populations and identifying resistance patterns.

What is an Antibiogram?

An antibiogram is a structured summary of antimicrobial susceptibility results across a defined group of microorganisms tested against multiple antimicrobial agents.

Antibiograms provide valuable insight into:

  • Susceptibility trends
  • Emerging resistance patterns
  • Comparative antimicrobial effectiveness
  • Population-level resistance monitoring

Our antibiogram reports classify isolates as:

  • Susceptible (S)
  • Intermediate (I)
  • Resistant (R)

These analyses support data-driven decision-making across multiple industries.

Quality & Accreditation Assurance

All AST and MIC data generated by Envirocare Laboratory is supported by a robust ISO/IEC 17025 quality framework, including:

  • Internal quality controls
  • Reference strains such as ATCC and NCTC
  • Traceable laboratory systems
  • CLSI and EUCAST-aligned methodologies

Testing may also incorporate VETCAST guidance where applicable for veterinary antimicrobial susceptibility interpretation.

Why Choose Envirocare Laboratory?

When antimicrobial accuracy, traceability, and regulatory alignment matter, Envirocare Laboratory provides dependable laboratory solutions supported by internationally recognised quality systems.

Our laboratory combines:

  • Technical expertise
  • Accredited quality systems
  • Traceable methodologies
  • Reliable turnaround
  • Industry-relevant interpretation support

Contact Envirocare Laboratory

For more information regarding AST, MIC testing, or Antibiogram Analysis services, contact our team:

📧 info@envirocarelab.co.za
📞 +27 18 294 4283
🌐 https://envirocarelab.co.za/

References

  1. Clinical and Laboratory Standards Institute (CLSI). Performance Standards for Antimicrobial Susceptibility Testing.
  2. European Committee on Antimicrobial Susceptibility Testing (EUCAST). Breakpoint Tables for Interpretation of MICs and Zone Diameters.
  3. World Health Organization (WHO). Antimicrobial Resistance Fact Sheets.
  4. ISO/IEC 17025:2017 — General requirements for the competence of testing and calibration laboratories.
  5. VETCAST – Veterinary Committee on Antimicrobial Susceptibility Testing.
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