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. Author manuscript; available in PMC: 2021 Apr 7.
Published in final edited form as: Anal Chem. 2020 Oct 22;92(21):14459–14465. doi: 10.1021/acs.analchem.0c02489

Figure 3.

Figure 3.

Bacterial response to different concentrations of antibiotic. (A) MIC measurement of erythromycin againstS. aureus ATCC 6538. OD600 represents the optical density at 600 nm after 24 h of drug treatment. MIC, highlighted as orange, was the lowest drug concentration under which OD600 was lower than 0.05. (B) Visualization of concentration-dependent killing of S. aureus ATCC 6538 by erythromycin after 1 h incubation time and colonies were counted after 20 h. Represented are average values of the cell count in logarithmic CFUs per mL (green bars, left scale) and the corresponding killing rate in percentage (red bars, right scale). The killing percentage was determined by the percentage of CFU differences at each concentration compared with the original CFU. The asterisk shows the MIC. (C) Single-cell MIP spectra of S. aureus ATCC 6538 treated with different concentrations of erythromycin. Quantification of (D) Nucleic Acids, Amide II, and Amide I MIP peaks and (E) the ratios of Amide II/Nucleic Acids and Amide I/Nucleic Acids.