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Profiling antibiotic resistance in Escherichia coli strains displaying differential antibiotic susceptibilities using Raman spectroscopy

Verma, T and Annappa, H and Singh, S and Umapathy, S and Nandi, D (2021) Profiling antibiotic resistance in Escherichia coli strains displaying differential antibiotic susceptibilities using Raman spectroscopy. In: Journal of Biophotonics, 14 (1).

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Official URL: https://doi.org/10.1002/jbio.202000231


The rapid identification of antibiotic resistant bacteria is important for public health. In the environment, bacteria are exposed to sub-inhibitory antibiotic concentrations which has implications in the generation of multi-drug resistant strains. To better understand these issues, Raman spectroscopy was employed coupled with partial least squares-discriminant analysis to profile Escherichia coli strains treated with sub-inhibitory concentrations of antibiotics. Clear differences were observed between cells treated with bacteriostatic (tetracycline and rifampicin) and bactericidal (ampicillin, ciprofloxacin, and ceftriaxone) antibiotics for 6 hr: First, atomic force microscopy revealed that bactericidal antibiotics cause extensive cell elongation whereas short filaments are observed with bacteriostatic antibiotics. Second, Raman spectral analysis revealed that bactericidal antibiotics lower nucleic acid to protein (I812/I830) and nucleic acid to lipid ratios (I1483/I1452) whereas the opposite is seen with bacteriostatic antibiotics. Third, the protein to lipid ratio (I2936/I2885 and I2936/I2850) is a Raman stress signature common to both the classes. These signatures were validated using two mutants, Δlon and ΔacrB, that exhibit relatively high and low resistance towards antibiotics, respectively. In addition, these spectral markers correlated with the emergence of phenotypic antibiotic resistance. Overall, this study demonstrates the efficacy of Raman spectroscopy to identify resistance in bacteria to sub-lethal concentrations of antibiotics. © 2020 Wiley-VCH GmbH

Item Type: Journal Article
Publication: Journal of Biophotonics
Publisher: Wiley-VCH Verlag
Additional Information: The copyright for this article belongs to Wiley-VCH Verlag.
Keywords: Atomic force microscopy; Bactericides; Discriminant analysis; Escherichia coli; Least squares approximations; Nucleic acids; Proteins; Raman spectroscopy; Solid solutions; Spectrum analysis, Antibiotic concentration; Antibiotic resistance; Antibiotic susceptibilities; Antibiotic-resistant bacteria; Drug-resistant strains; Inhibitory concentration; Partial least squares - discriminant analysis; Rapid identification, Antibiotics, antiinfective agent, antibiotic resistance; bacterium; Escherichia coli; genetics; microbial sensitivity test; Raman spectrometry, Anti-Bacterial Agents; Bacteria; Drug Resistance, Microbial; Escherichia coli; Microbial Sensitivity Tests; Spectrum Analysis, Raman
Department/Centre: Division of Interdisciplinary Sciences > Centre for Biosystems Science and Engineering
Date Deposited: 20 Feb 2023 11:35
Last Modified: 20 Feb 2023 11:35
URI: https://eprints.iisc.ac.in/id/eprint/80433

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