Raman and infrared spectroscopy of WHO essential antibiotics

Area of Science:

• Biochemistry
• Spectroscopy
• Computational Chemistry

Background:

• Antimicrobial resistance (AMR) is a global health crisis requiring better understanding of antibiotic mechanisms.
• Vibrational spectroscopy (IR and Raman) is promising for AMR research, but detailed spectral data for key antibiotics is lacking.

Purpose of the Study:

• To perform a comparative vibrational analysis of World Health Organization Essential Medicines List (EML) antibiotics.
• To establish validated spectral fingerprints for antibiotic identification and classification using IR and Raman spectroscopy combined with DFT calculations.

Main Methods:

• Comparative analysis of representative EML antibiotics using Infrared (IR) and Raman spectroscopy with multiple excitation wavelengths.
• Density Functional Theory (DFT) calculations (ωB97X-D3/6-31+G*) to complement experimental data.
• Alignment of experimental and computational spectra for mode and functional group assignment.

Main Results:

• Identification of distinct vibrational signatures for β-lactams, aminoglycosides, glycopeptides, lipopeptides, quinolones, and ansamycins.
• High agreement between experimental and DFT-calculated spectra, validating the spectral fingerprints.
• Specific spectral regions and bands were assigned to key functional groups for each antibiotic class.

Conclusions:

• The study provides a comprehensive spectral reference framework for essential antibiotics.
• Validated spectral fingerprints support antibiotic identification, classification, and mechanistic studies in AMR research.
• This work lays the foundation for using vibrational spectroscopy in drug monitoring, resistance profiling, and high-throughput screening.