Liofilchem® Integral System Enterobacteria for 20 tests

The INTEGRAL SYSTEM ENTEROBACTERIA is a 24-well diagnostic system designed for biochemical identification and antimicrobial susceptibility testing (AST) of enterobacteria. Each well contains desiccated substrates, including biochemical reagents for bacterial identification and antibiotics for susceptibility testing. The system is inoculated with a bacterial suspension, incubated, and interpreted based on colorimetric changes.

Key Features

1. Biochemical Identification:
   • Includes 10 wells (1-LDC to 10-OX) with substrates for various biochemical reactions to identify enterobacteria.
   • Results in a 4-digit numerical code for organism identification.
2. Antibiotic Susceptibility Testing (AST):
   • Includes 13 wells (11-AK to 23-SXT) with antibiotics at NCCLS-compliant concentrations for testing bacterial growth inhibition.
   • A control well (24-C) ensures the reliability of the inoculum and test conditions.
3. Broad Range of Applications:
   • Identifies clinically relevant enterobacteria, such as Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Salmonella spp., and others.
   • Determines susceptibility to antibiotics like amikacin, cefotaxime, ciprofloxacin, and co-trimoxazole.

Kit Contents

• 20 INTEGRAL SYSTEM ENTEROBATTERI systems (20 tests)
• 20 vials of Suspension Medium (7.0 mL each)
• 20 Oxidase Discs
• Instruction sheet

Reagents Not Included (Necessary for Testing):

• Vaseline Oil (80278): Maintains anaerobic conditions.
• Physiological Solution (20095): Used for inoculum preparation.
• Kovac’s Reagent (80270): Required for indole test.
• General microbiology lab materials (e.g., inoculation loops, slides).

System Configuration

Principle of the Method

1. Biochemical Identification:
   • Tests enzymatic and fermentation reactions using substrates in wells 1-LDC to 10-OX.
   • Results are interpreted by color changes (e.g., violet for positive lysine decarboxylase).
2. Antibiotic Susceptibility Testing (AST):
   • Tests bacterial growth inhibition in wells containing antibiotics.
   • Results are categorized as:
     • Blue: Sensitive (S)
     • Grey: Intermediate (I)
     • Yellow: Resistant (R)

Procedure

1. Prepare bacterial suspension in physiological solution to 0.5 McFarland turbidity.
2. Inoculate:
   • 0.2 mL in wells 1-10 for biochemical tests (add vaseline oil to wells 1, 2, 3, and 8).
   • 0.2 mL in wells 11-24 for AST.
3. Incubate at 36°C ± 1°C for 18-24 hours.
4. Add reagents (e.g., Kovac’s reagent to well 4-IND; oxidase disc to well 10-OX) as needed.
5. Interpret results using the provided tables.

Numerical Code Formation

The 10 biochemical tests are divided into 3 groups of 3 tests and 1 group of 1 test. Each test is assigned a positiveness value of 1, 2, or 4, based on its order in the group. A 0 is assigned if all tests in a group are negative.

Numerical Code Example

Numerical Code: 3300

This code corresponds to Escherichia coli in the Numerical Code Table.

Numerical Code Table

Below is an excerpt from the Numerical Code Table used for bacterial identification:

Note: Variable reactions (V) in some species may lead to alternate codes. Refer to the full Numerical Code Table in the documentation for all combinations.

Example of Code-Based Identification

1. Perform biochemical tests using wells 1-LDC to 10-OX.
2. Record positive/negative reactions.
3. Calculate the numerical code using the positiveness values.
4. Match the code with the Numerical Code Table to identify the microorganism.

Biochemical Identification Table

Quality Control

• ATCC reference strains (e.g., Escherichia coli ATCC 25922, Salmonella typhimurium ATCC 14028) ensure the reliability of biochemical identification and AST.

Storage

• Store at 2-8°C in original packaging, away from heat sources.

Key Benefits

• Simultaneous bacterial identification and susceptibility testing in one system.
• Compatible with standard laboratory workflows.
• Provides accurate results consistent with traditional methods.
• Time-efficient (simultaneous identification and AST).
• Requires less manual intervention.
• Provides standardized results.

This system is ideal for clinical microbiology laboratories conducting routine identification and susceptibility testing of enterobacteria.