Liofilchem® Fosfomycin FOS Antimicrobial Susceptibility Discs

Liofilchem® Fosfomycin FOS Discs (200 µg) are high-quality antimicrobial susceptibility testing (AST) discs designed for in vitro use with the Kirby-Bauer disk diffusion method on Mueller-Hinton agar supplemented with glucose-6-phosphate (G6P). Each disc contains 200 micrograms of Fosfomycin, a phosphonic acid derivative antibiotic with bactericidal activity against a broad range of Gram-negative and some Gram-positive bacteria. These discs are manufactured under ISO 9001 and ISO 13485 standards, ensuring accuracy, sterility, and consistency for clinical diagnostics and resistance surveillance.

Key Features

• High-potency formulation: Each disc contains 200 µg of Fosfomycin to ensure accurate zone interpretation in accordance with international guidelines.
• Broad-spectrum activity: Effective against Escherichia coli, Enterococcus faecalis, Klebsiella pneumoniae, Proteus mirabilis, Enterobacter spp., and multidrug-resistant uropathogens.
• CLSI and EUCAST compliant: Designed for use with standardized AST methods that include glucose-6-phosphate supplementation.
• Sterile and stable: Packaged in sealed cartridges or canisters with desiccant to preserve efficacy and extend shelf life.
• Color-coded labeling: Enables fast and accurate disc identification in busy laboratories.

Applications and Use Cases

1. Clinical Microbiology

Used in hospital and diagnostic laboratories to:

• Determine the susceptibility of:
  • Escherichia coli, especially in uncomplicated urinary tract infections (UTIs)
  • Extended-spectrum β-lactamase (ESBL)-producing Enterobacterales
  • Carbapenem-resistant Klebsiella pneumoniae (CRE)
  • Enterococcus faecalis and Staphylococcus saprophyticus
• Support antibiotic selection in:
  • Community- and hospital-acquired UTIs
  • Infections caused by multidrug-resistant uropathogens

2. Antimicrobial Stewardship and Surveillance

• Monitor Fosfomycin resistance patterns, especially in urology and nephrology patient populations.
• Track susceptibility in ESBL and CRE isolates as part of infection control programs.

3. Research and Development

• Evaluate Fosfomycin efficacy against biofilm-forming or resistant strains.
• Study the synergy of Fosfomycin in combination therapies (e.g., with aminoglycosides or carbapenems).
• Test novel formulations or delivery systems in pharmaceutical development.

Use Instructions

1. Prepare Mueller-Hinton agar supplemented with 25 µg/mL glucose-6-phosphate (G6P) as required for Fosfomycin testing.
2. Standardize bacterial suspension to 0.5 McFarland turbidity.
3. Inoculate the plate uniformly with a sterile swab.
4. Apply one Fosfomycin disc (200 µg) using sterile forceps or a disc dispenser.
5. Incubate at 35 ± 2 °C for 16–18 hours.
6. Measure the diameter of the inhibition zone in millimeters.
7. Interpret using the latest CLSI or EUCAST breakpoints, considering organism-specific criteria (e.g., E. coli from urine).

Storage and Shelf Life

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

Liofilchem® Fosfomycin FOS Discs (200 µg) provide a standardized and effective tool for detecting bacterial susceptibility to Fosfomycin, particularly for urinary pathogens and multidrug-resistant Enterobacterales. Backed by ISO-certified manufacturing and aligned with CLSI/EUCAST guidelines, these discs support clinical decision-making, resistance tracking, and antibiotic stewardship. They are an essential addition to the modern microbiology laboratory's toolkit for combating antimicrobial resistance.