A new test of disk-diffusion to help in staphylococci identification

Area of Science:

• Microbiology
• Clinical Diagnostics
• Bacteriology

Background:

• Accurate identification of staphylococci species is crucial for clinical diagnostics and effective treatment.
• Traditional carbohydrate fermentation tests in tubes (SCFT) are time-consuming and require extensive material preparation.
• There is a need for improved, efficient methods for staphylococcal species identification in clinical microbiology.

Purpose of the Study:

• To develop and evaluate a modified carbohydrate fermentation test (MCFT) using a disk-diffusion assay.
• To compare the efficacy of MCFT with the standard carbohydrate fermentation in tubes (SCFT) for identifying clinical staphylococci.
• To assess the sensitivity and specificity of MCFT for differentiating staphylococci species.

Main Methods:

• A modified carbohydrate fermentation test (MCFT) was performed using a disk-diffusion assay on a peptone-free agar medium.
• Results from MCFT were compared against the standard method of carbohydrate fermentation in tubes (SCFT).
• The study utilized both ATCC reference strains and 646 clinical isolates of staphylococci.

Main Results:

• MCFT successfully identified 12 different ATCC staphylococci species and 646 clinical isolates.
• The sensitivity of MCFT ranged from 91.6% to 100% across different carbohydrates.
• The specificity of MCFT ranged from 99.6% to 100% for the carbohydrates evaluated.

Conclusions:

• MCFT is a highly sensitive and specific method for identifying clinical staphylococci species.
• MCFT offers a significant advantage over SCFT by reducing preparation time and simplifying the process.
• This disk-diffusion assay is a practical and efficient alternative for staphylococci identification in clinical and research laboratories.