Application of electrode method for rapid diagnosis of the sensitivity of VTEC O157

Objective Using experimental model of bacterial oxidation reduction,the author rapidly diagnosed the sensitivity of VTEC O157 by combining technology of electrode and computer.Method After antibiotic treatment,the drug was adhered to the surface of the working electrode and a voltage with 10 mV / s increasing rate was input between the working electrode and the counter electrode.The computer simultaneously recorded the voltammogram of voltage in the range of 0.00-1.00 V.Determined the sensitivity of VTEC O157 to antibiotic according to the value of peak current on the voltammogram.If the peak current value is less than or equal to 2.5 μA,it is sensitive(S);if the peak current value is more than or equal to 3.0 μA,it is resistant(R).And if the peak current value is of 2.6-2.9 μA,it is moderately sensitive(M).Agar diffusion method was used to diagnose drug sensitivity of VTEC O157 in the control group.Findings The electrode method can complete the recording of voltammogram and the relative peak current value measurement in two minutes.The testing of VTEC O157 strains with 13 kinds of antibiotics showed that: VTEC O157 was insensitive to Penicillin and Lincomycin,moderately sensitive to Ampicillin and Erythromycin,and sensitive to the remaining nine antibiotics.The results are consistent with those obtained by the agar diffusion method.Conclusion The sensitivity of VTEC O157 to antibiotic can be indirectly determined according to the value of voltammogram peak current on voltammogram.Peak current value of the electrode method is inversely proportional to the diameter of inhibition zone by agar diffusion method.