Classification and identification of enterococci: a comparative phenotypic, genotypic, and vibrational spectroscopic...

Area of Science:

• Clinical Microbiology
• Spectroscopy
• Bacterial Identification

Background:

• Enterococci are a leading cause of hospital-acquired infections worldwide.
• Accurate species-level identification of enterococci is crucial for effective treatment.
• Conventional identification methods can be time-consuming.

Purpose of the Study:

• To compare vibrational spectroscopic techniques (FT-IR, Raman) with conventional phenotypic and genotypic methods for enterococci identification.
• To evaluate the discriminative capacity and reproducibility of vibrational spectroscopy.
• To assess the potential of vibrational spectroscopy as a routine clinical microbiology tool.

Main Methods:

• Fourier Transform-Infrared (FT-IR) spectroscopy with hierarchical cluster analysis.
• Polymerase Chain Reaction (PCR) for species-specific genes.
• 16S RNA sequencing.
• Confocal Raman microspectroscopy.
• FT-IR attenuated total reflectance spectroscopy.
• FT-IR microspectroscopy.

Main Results:

• FT-IR classification showed discrepancies with some automated phenotypic systems but was confirmed by genotypic methods (PCR, 16S RNA sequencing).
• Vibrational spectroscopic techniques demonstrated high discriminative capacity across multiple laboratories and methods.
• Reproducibility was confirmed by independent validation in three different labs.

Conclusions:

• Vibrational spectroscopic techniques are reliable and reproducible for identifying enterococci species.
• These methods offer a promising alternative to conventional techniques in clinical microbiology.
• The speed, ease of use, and economy of vibrational spectroscopy support its potential for routine application.