Liofilchem® Fusidic acid FC Antimicrobial Susceptibility Discs

Liofilchem® Fusidic Acid FC Discs 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 is impregnated with either 10 µg or 30 µg of Fusidic acid, a steroid-like antibiotic that inhibits bacterial protein synthesis by targeting elongation factor G (EF-G). Fusidic acid is particularly effective against Gram-positive cocci, especially Staphylococcus aureus, including some methicillin-resistant strains (MRSA). These discs are manufactured under strict ISO 9001 and ISO 13485 certified quality systems for consistent and reliable performance.

Key Features

• Dual concentration options: Available in 10 µg and 30 µg to accommodate different interpretive standards and testing needs.
• Staphylococcal targeting: Highly effective against Staphylococcus aureus, including strains resistant to beta-lactams.
• CLSI/EUCAST compatibility: Suitable for susceptibility testing in accordance with international guidelines.
• Sterile, ready-to-use format: Packaged in sealed canisters or cartridges with desiccant to preserve disc integrity and performance.
• Color-coded disc labels: Ensure easy identification of disc strength and drug type.

Applications and Use Cases

1. Clinical Microbiology

Used in diagnostic laboratories to:

• Assess susceptibility of Staphylococcus aureus, including:
  • Methicillin-sensitive S. aureus (MSSA)
  • Methicillin-resistant S. aureus (MRSA)
  • Coagulase-negative staphylococci (CoNS)
• Support treatment decisions in cases of:
  • Skin and soft tissue infections (SSTIs)
  • Bone and joint infections (e.g., osteomyelitis)
  • Ocular infections (topical fusidic acid formulations)

2. Resistance Surveillance and Stewardship

• Monitor fusidic acid resistance in staphylococcal isolates.
• Track regional or institutional resistance patterns, particularly in dermatology, orthopedics, and ophthalmology-related infections.

3. Research and Development

• Compare activity of Fusidic acid with other anti-staphylococcal agents (e.g., mupirocin, clindamycin).
• Evaluate synergy or antagonism in combination therapy studies.
• Support development of topical or systemic Fusidic acid-based treatments.

Use Instructions

1. Prepare Mueller-Hinton agar plates as per standard microbiological guidelines.
2. Standardize inoculum to 0.5 McFarland turbidity using a densitometer or visual standard.
3. Inoculate the agar surface evenly with the test organism using a sterile swab.
4. Apply one Fusidic acid disc (10 µg or 30 µg) using sterile forceps or a disc dispenser.
5. Incubate at 35 ± 2 °C for 16–18 hours under ambient atmospheric conditions.
6. Measure the diameter of the inhibition zone in millimeters.
7. Interpret results according to EUCAST or local guidelines (note: CLSI does not currently define breakpoints for Fusidic acid).

Storage and Shelf Life

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

Liofilchem® Fusidic Acid FC Discs (10 µg and 30 µg) offer a precise, standardized approach for detecting staphylococcal susceptibility to an important topical and systemic antibiotic. Their dual-concentration availability makes them suitable for a range of research and clinical applications, especially where MRSA and CoNS pose a therapeutic challenge. Backed by ISO-certified manufacturing and validated for high accuracy, these discs support antimicrobial stewardship and treatment optimization in both human and veterinary healthcare.