Liofilchem® Cefoxitin Fox Antimicrobial Susceptibility Discs, 30 µg

Liofilchem® Cefoxitin Discs (30 µg) are high-quality antimicrobial susceptibility testing (AST) discs intended for in vitro diagnostic use with the Kirby-Bauer disk diffusion method on Mueller-Hinton agar. Each disc contains 30 µg of Cefoxitin, a second-generation cephamycin antibiotic with broad-spectrum activity, especially useful for the detection of methicillin-resistant Staphylococcus aureus (MRSA) and AmpC beta-lactamase-producing Enterobacterales. These discs are manufactured in compliance with ISO 9001 and ISO 13485 quality standards, ensuring accuracy and consistency in susceptibility profiling.

Key Features

• Standardized potency: Precisely loaded with 30 µg of Cefoxitin per disc.
• Diagnostic utility: Recommended by CLSI and EUCAST as a surrogate marker for detecting mecA-mediated resistance (MRSA) and inducible AmpC beta-lactamase expression.
• Ready-to-use format: Supplied sterile in cartridges or canisters to preserve stability and ease of handling.
• Color-coded identification: Clearly labeled for fast recognition in high-throughput labs.
• Extended shelf life: Stable under refrigerated storage for 2–3 years from manufacture.

Applications and Use Cases

1. Clinical Microbiology

Used in hospital and reference labs to:

• Detect methicillin resistance in Staphylococcus aureus (MRSA) via surrogate Cefoxitin testing.
• Identify AmpC-producing Enterobacterales by reduced inhibition zones.
• Assist clinicians in antibiotic decision-making for:
  • Skin and soft tissue infections (SSTIs)
  • Respiratory tract infections
  • Bacteremia and sepsis cases

2. Infection Control and Surveillance

• Routinely used in MRSA screening programs using nasal or wound swabs.
• Supports infection control interventions by detecting and tracking resistant strains.

3. Research and Development

• Study resistance mechanisms including mecA/mecC gene expression.
• Investigate prevalence and behavior of AmpC enzymes in Gram-negative isolates.
• Develop new diagnostic algorithms using surrogate markers.

Use Instructions

1. Prepare Mueller-Hinton agar plates according to standard microbiological protocols.
2. Standardize inoculum to a 0.5 McFarland turbidity standard.
3. Inoculate agar plates with the test organism using a sterile swab.
4. Apply one Cefoxitin disc (30 µg) using sterile forceps or a disc dispenser.
5. Incubate at 35 ± 2 °C for 16–18 hours in ambient air.
6. Measure the inhibition zone in millimeters.
7. Interpret results using the latest CLSI or EUCAST guidelines, noting breakpoints for MRSA or AmpC detection.

Storage and Shelf Life

• Storage Temperature: 2–8 °C (refrigerated)
• Shelf Life: Typically 24–36 months from the date of manufacture when stored in unopened packaging with desiccant.

Liofilchem® Cefoxitin FOX Discs (30 µg) are essential tools for the reliable detection of methicillin resistance in Staphylococcus species and AmpC-mediated beta-lactam resistance in Gram-negative bacteria. Their role as a phenotypic surrogate marker makes them indispensable in clinical decision-making and infection control efforts. Manufactured to the highest standards, these discs ensure dependable results for laboratories focused on combating antimicrobial resistance.