Assessment of the antimicrobial effects of sodium hypochlorite on by DO-labeled single-cell Raman micro-spectroscopy.

OBJECTIVES

To systematically evaluate the feasibility of DO-labeled single-cell Raman micro-spectroscopy in drug resistance research and test the susceptibility of ()to sodium hypochlorite.

METHODS

1. The growth of in different doses of DO and the regularity of DO intake were evaluated through absorbance measurement and DO-labeled single-cell Raman micro-spectroscopy to examine the universality of DO-labeled single-cell Raman micro-spectroscopy in bacterial resistance research. 2) Broth dilution method and absorbance measurement were performed to determine the minimum inhibitory concentration (MIC) of NaClO against and the MIC based on metabolic activity (MIC-MA) via DO-labeled single-cell raman micro-spectroscopy.

RESULTS

1. The growth of was not significantly inhibited by ≤40% DO in the medium. could actively metabolize DO and exhibit a C-D ratio in specific areas of Raman micro-spectroscopy results. The C-D ratio of at the stationary phase was positively correlated with DO concentration. 2) The MIC and MIC-MA of NaClO against were 0.45 and 0.9 g·L, respectively. The concentration of MIC-MA was twice that of MIC.

CONCLUSIONS

DO-labeled single-cell Raman micro-spectroscopy is important in screening antimicrobial agents and evaluating the efficacy of antimicrobial agents. It is suitable for evaluating the effect of drugs on bacterial metabolic activities. NaClO showed an effective antimicrobial activity against . ceased propagation yet remained highly metabolically active when it was exposed to NaClO at the MIC level. The metabolic activity of most cells was inhibited only when they were exposed to NaClO at the MIC-MA level.