Sensing the Bactericidal and Bacteriostatic Antimicrobial Mode of Action Using Raman Deuterium Stable Isotope Probing (DSIP) in Escherichia coli .

The mode of action of antibiotics can be broadly classified as bacteriostatic and bactericidal. The bacteriostatic mode leads to the arrested growth of the cells, while the bacteriocidal mode causes cell death. In this work, we report the applicability of deuterium stable isotope probing (DSIP) in combination with Raman spectroscopy (Raman DSIP) for discriminating the mode of action of antibiotics at the community level. Escherichia coli, a well-known model microbe, was used as an organism for the study. We optimized the concentration of deuterium oxide required for metabolic activity monitoring without compromising the microbial growth. Our findings suggest that changes in the intensity of the C-D band in the high-wavenumber region could serve as a quantifiable marker for determining the antibiotic mode of action. This can be used for early identification of the antibiotic's mode of action. Our results explore the new perspective that supports the utility of deuterium-based vibrational tags in the field of clinical spectroscopy. Understanding the antibiotic's mode of action on bacterial cells in a short and objective manner can significantly enhance the clinical management abilities of infectious diseases and may also help in personalized antimicrobial therapy.