Liofilchem® SensiTest Gram-negative

The Sensi Test Gram-Negative System is an advanced diagnostic tool designed for determining the antimicrobial susceptibility of gram-negative bacteria and enterococci. This system utilizes a 24-well plate containing desiccated antibiotics and growth medium for the reliable and accurate evaluation of bacterial resistance profiles. The test is based on the broth microdilution method and provides results that classify bacteria as Sensitive (S), Intermediate (I), or Resistant (R), adhering to EUCAST (European Committee on Antimicrobial Susceptibility Testing) or CLSI (Clinical and Laboratory Standards Institute) interpretative criteria.

Kit Contents

Each Sensi Test Gram-Negative System kit includes:

• 20 Test Systems: 24-well microplates preloaded with 23 antibiotics at standardized concentrations and 1 growth control well.
• 20 Vials of Suspension Medium (7 mL per vial): Pre-formulated medium for inoculum preparation.
• Instruction Manual: Detailed protocols for handling, testing, and result interpretation.
• 20 Test Result Forms: For recording and reporting MIC values and susceptibility profiles.

Antibiotics in the System

The plate includes antibiotics from various classes, covering a wide range of therapeutic agents for gram-negative bacterial infections. The antibiotic configuration is as follows:

1. Amikacin (AK): 32 µg/mL
2. Gentamicin (CN): 8 µg/mL
3. Tobramycin (TOB): 8 µg/mL
4. Ampicillin/Sulbactam (AMS): 32/16 µg/mL
5. Amoxicillin/Clavulanic Acid (AUG): 32/16 µg/mL
6. Mezlocillin (MEZ): 128 µg/mL
7. Piperacillin/Tazobactam (TZP): 128/4 µg/mL
8. Ticarcillin/Clavulanic Acid (TCC): 128/2 µg/mL
9. Fosfomycin (FOS): 200 µg/mL
10. Nitrofurantoin (F): 128 µg/mL
11. Cefoperazone (CFP): 64 µg/mL
12. Cefotaxime (CTX): 64 µg/mL
13. Ceftazidime (CAZ): 32 µg/mL
14. Ceftriaxone (CRO): 64 µg/mL
15. Cefuroxime (CXM): 32 µg/mL
16. Nalidixic Acid (NA): 32 µg/mL
17. Lomefloxacin (LOM): 8 µg/mL
18. Ciprofloxacin (CIP): 4 µg/mL
19. Levofloxacin (LEV): 8 µg/mL
20. Pefloxacin (PEF): 8 µg/mL
21. Teicoplanin (TEC): 32 µg/mL
22. Aztreonam (ATM): 32 µg/mL
23. Co-trimoxazole (SXT): 8 µg/mL
24. Growth Control Well (C): Contains growth medium without antibiotics.

Principle of the Test

The Sensi Test Gram-Negative System works by inoculating a standardized bacterial suspension into the wells of the plate. Each well contains a specific antibiotic at a defined concentration. After inoculation, the plates are incubated at 36°C ± 1°C for 18–24 hours. The presence or absence of bacterial growth is indicated by a color change in the growth indicator.

• Blue: No growth (Inhibited).
• Gray: Partial growth (Intermediate inhibition).
• Yellow: Significant growth (Resistant).

Applications

This system is suitable for:

1. Urinary Pathogens: Testing susceptibility of urinary enterococci and enterobacteria.
2. Other Clinical Samples: Analyzing enterobacteria isolated from blood, respiratory, or wound infections.
3. Non-Fermenting Bacteria: Evaluating resistance in species such as Pseudomonas aeruginosa and Acinetobacter spp.
4. Veterinary Pathogens: Testing gram-negative bacteria isolated from animal infections.

Key Features and Benefits

• Comprehensive Antibiotic Range: Covers multiple therapeutic classes including beta-lactams, aminoglycosides, fluoroquinolones, and sulfonamides.
• Ease of Use: Preloaded antibiotics save time and reduce the need for manual preparation.
• Standardized Results: Provides reliable MIC values following CLSI and EUCAST guidelines.
• Growth Control Well: Ensures microbial viability and validates the test.
• High Compatibility: Suitable for use with multi-channel pipettes for efficient inoculation.
• Quality Assurance: Each batch undergoes rigorous quality control testing with reference bacterial strains.

Storage and Stability

• Storage Conditions: Store at 2–8°C in the original packaging, away from light.
• Stability: Stable for 24 months under recommended conditions. Can withstand temporary temperature variations during transport (up to 4 days at 18–25°C or 48 hours at 35–39°C) without compromising performance.

Quality Control

The system is validated using internationally recognized bacterial reference strains:

• Escherichia coli ATCC® 25922
• Pseudomonas aeruginosa ATCC® 27853
• Enterobacter cloacae ATCC® 13048
• Enterococcus faecalis ATCC® 19433
• Klebsiella pneumoniae ATCC® 13883

Precautions

• For In Vitro Diagnostic Use only.
• Ensure proper aseptic techniques to prevent contamination.
• Only trained laboratory professionals should handle the system.
• Decontaminate and dispose of used materials according to laboratory guidelines.

Packaging Information

• REF: 76010
• Kit Size: 20 tests
• Suspension Medium: 20 vials, 7 mL each
• Storage Temperature: 2–8°C

This reliable, easy-to-use system is an essential tool for clinical microbiology labs to assess antimicrobial resistance in gram-negative bacteria efficiently and accurately.