Evaluation Of Bacterial Sensitivity To Antibiotics Based On Surface-enhanced Raman Spectroscopy Technology

Bacterial infection can lead to diseases in human body.Long-term use of antibiotics can reduce or even lose the sensitivity of bacteria to antibiotics.It can seriously lead to the production of super bacteria,causing irreversible harm to human body.Bacterial resistance to broad-spectrum antibiotics has become a global problem to be solved urgently.Rapid and accurate evaluation of bacterial sensitivity to antibiotics has become important in research.Surface-enhanced Raman spectroscopy(SERS)technology has the advantage of simple sample preparation,high sensitivity and out of the influence of water,which is widely used in microbial detection nowadays.In this study,surface-enhanced Raman spectroscopy technology was used to establish a rapid method for detecting bacterial antibiotic susceptibility test(AST).The effect of different antibiotics to bacteria was evaluated by analyzing the change of Raman spectrum intensity in vitro.Escherichia coli O157: H7 and Staphylococcus aureus were treated with different antibiotics respectively,then the aptamers were used to bind with bacteria specifically,the silver nanoparticles were reduced in situ,and Raman spectrum detection was carried out.The minimum inhibitory concentration(MIC)of antibiotics could be detected rapidly within one hour by Raman spectrum detection.In 2 hours,it was found that the intensity of Raman signal increased when the concentration of antibiotics was lower than MIC,and the number of bacteria increased under the action of micro antibiotics.This method can determine the MIC value in a short time,and Raman spectroscopy was used to detect the phenomenon that micro antibiotics stimulated the growth of bacteria,which will provide new guidance for the evaluation of new drugs in the future.In this study,bioluminescent Shigella Flexneri in vivo model was constructed and treated with ciprofloxacin to observe the bioluminescent signal,and then determine the sensitivity of bacteria in animals to antibiotics.Firstly,the bioluminescent Shigella Flexneri in the organ abrasives of infected mice were detected by surface-enhanced Raman spectroscopy technology.It was found that under the effect of effective antibiotic concentration,the signal intensity of bacterial Raman spectrum decreased and the growth of bacteria was inhibited.Then bioluminescence signal of bioluminescent bacteria in infected mice and treated mice were continuously monitored by small animals imaging system.When the concentration of antibiotics is lower than MIC,the phenomenon of enhanced bioluminescent signal can be found,which shows that the number of bacteria increases at this time,and the results of in vivo imaging technology are consistent with the results of Raman spectrum detection.The sensitivity of bacteria to antibiotics detected by Raman spectrum was verified by in vivo bioluminescent imaging technology,it also provides a new reference for clinical antibiotic dosage use.