Rapid identification of drug resistance of Escherichia coli based on electrochemical square wave voltammetry of resazurin

Abstract

Objective: To evaluate the antibiotic resistance of five foodborne Escherichia coli clinical isolates to ciprofloxacin, gentamicin and ampicillin. Methods: Based on the theory of electron transfer during bacterial energy metabolism and the introduction of resazurin as a redox probe, an electrochemical square wave voltammetry （SWV） method based on bladed tensin-mediated rapid identification of E. coli drug resistance was established. Results: The electrochemical square wave voltammetry values of E. coli at different concentrations mediated by resazurin were determined, and there was a good linear relationship between the E. coli concentration and the oxidized peak current （I） of resazurin in the range of 1.69×102～1.69×108 CFU/mL, with the regression equation of Y=-0.156 0X-2.965 5, and R2=0.977 5; When performing the determination of E. coli drug resistance, the drug sensitivity test standard was developed by Clinical and Laboratory Standards Institute （CLSI）. The oxidized peak current （I0） of resazurin and the oxidized peak current （I-a） obtained by E. coli after directly interacting with resazurin were used as the control, and the oxidized peak current （I+a） obtained by E. coli after treating it with antibiotics and interacting with resazurin was determined. The value of bacterial activity VETA was introduced as VETA as an indicator for the identification of bacterial resistance by electrochemical square wave voltammetry, and established a rapid electrochemical drug sensitivity test method for E. coli mediated by resazurin. The established method was used to detect the resistance of five clinical isolates of foodborne E. coli to three antibiotics, and VETA=50 was used as the critical value for determining bacterial sensitivity and resistance, and the results of the drug sensitivity tests were all in accordance with the results of the paper diffusion method. The VETA=50 was used as the critical value for determining bacterial susceptibility and resistance, and all the results were consistent with the results of the paper diffusion method, and the paper diffusion method required 18 h to report the results, whereas this method required only 2 h. Conclusion: Our electrochemical square-wave voltammetry method based on the resazurin-mediated rapid discrimination of E. coli drug resistance is able to accurately and rapidly detect the antibiotics resistance of the five foodborne clinical isolates of E. coli to ciprofloxacin, gentamicin, and ampicillin.

Keywords

• escherichia coli
• drug resistance
• rapid detection
• resazurin
• electron transport chain
• square wave voltammetry