Liofilchem® Oxi/FermPluri-Test

The Oxi/FermPluri-Test by Liofilchem is a diagnostic system designed for the identification of Gram-negative, oxidase-positive bacteria using biochemical reactions. 

The Oxi/FermPluri-Test is a 12-sector system containing specialized culture media to identify Gram-negative, oxidase-positive bacteria. It performs 14 biochemical reactions to detect specific metabolic properties of the microorganisms. Identification is achieved by analyzing the color changes in the culture media after incubation and assigning a code number for comparison in a provided codebook.

Kit Contents

• Tests: 10 or 25 Oxi/FermPluri-Test systems per package.
• Instructions: 1 instruction sheet and a data chart for recording biochemical reaction results.

Required but Not Included

• KOVAC’S Reagent (Ref. 80271): For indole reaction.
• Oxi/FermPluri-Test Codebook (Ref. 71708): For bacterial identification.
• Oxidase Test Sticks/Swabs/Discs (Ref. 88029 / 88003 / 88004): For preliminary oxidase testing.
• General microbiology lab materials.

Biochemical Reactions

Each of the 12 sectors evaluates a specific reaction:

1. Anaerobic Glucose: Fermentation of glucose.
2. Arginine: Arginine decarboxylation in anaerobiosis.
3. Lysine: Lysine decarboxylation in anaerobiosis.
4. Lactose/N2: Lactose fermentation and nitrogen production.
5. Sucrose/Indole: Oxidation of sucrose and production of indole.
6. Xylose: Xylose oxidation.
7. Aerobic Glucose: Glucose oxidation.
8. Maltose: Maltose oxidation.
9. Mannitol: Mannitol oxidation.
10. Phenylalanine: Phenylalanine deamination.
11. Urea: Urea hydrolysis.
12. Citrate: Citrate utilization.

Test Procedure

1. Sample Collection: Use isolated Gram-negative, oxidase-positive colonies from non-selective agar (e.g., Columbia or Tryptic Soy Agar with 5% sheep blood).
2. Pre-tests: Perform Gram staining and oxidase tests to confirm suitability of the sample.
3. Inoculation:
   • Use the provided inoculation needle to transfer the bacterial colony into the system.
   • Insert and break the needle within the system for anaerobic conditions in specific sectors.
   • Punch holes in aerobic sectors to support aerobic growth.
4. Incubation: Incubate at 36 ± 1°C for 48 hours.

Result Interpretation

• After 24 hours, observe the urea sector for a preliminary reaction.
• After 48 hours, record the color changes in all sectors.
• For the indole test, inject KOVAC’S reagent and observe for a pink-red color indicating a positive result.
• Record the results and assign values (4, 2, 1, or 0) based on positive reactions to form a 5-digit code for bacterial identification.

Quality Control

The system is tested using reference bacterial strains (e.g., Pseudomonas aeruginosa, Aeromonas hydrophila, Stenotrophomonas maltophilia). Each test follows specified procedures to ensure reliability.

Storage and Disposal

• Storage: Keep at 2–8°C, protected from light.
• Disposal: Decontaminate and discard used systems following laboratory protocols for infectious materials.

References

1. Abbott, S.L. (2003): Manual of Clinical Microbiology (8th ed.), ASM.
2. Edwin, H. Lenette (1985): Manual of Clinical Microbiology (4th ed.), ASM.
3. Ewing, W.H. (1973): Differentiation of Enterobacteriaceae by Biochemical Reactions.
4. Liofilchem internal archives (2012).

Product Details

• Oxi/FermPluri-Test (10 tests): Ref. 78620.
• Oxi/FermPluri-Test (25 tests): Ref. 78621.

This table summarizes the reactions and their color indicators for easy reference during the testing process.