RESUMO
Sensitive and rapid tests of Escherichia coli drug sensitivity is very important for health of human and animals. An E. coli immunosensor was built based on electrochemical detection and immune detection technologies, through pretreating screen-printed electrodes, and analyzing the optimal reaction concentration of antigen antibody binding with the AC impedance method. Based on the detection system combining the immunosensor and electrochemical workstation, tests were carried out to measure the accuracy of E. coli concentration and drug sensitivity, and error of the detection system was calibrated in accordance with data from the electrochemical workstation. E. coli O157:H7 can be detected in the range of 103 cfu/ml ~ 1012 cfu/ml, and the detection error controlled within 5%. Results from the electrochemical workstation and those from the detection device were consistent, and both demonstrated a greater inhibitory effect of antibiotics on E. coli than on Bacillus subtilis. The electrochemical detection system is highly efficient and accurate, and could be widely applied to E. coli drug sensitivity tests in clinical medicine.