Abstract：Objective To confirm the reliability and the effectiveness of 96 dot agar dilution method in antimicrobial susceptibility test, the results were contrasted to those of the international standard of broth microdilution method. Methods The control strain E. coli ATCC25922 and clinical isolates E. coli were used to be tested the minimal inhibitory concentration (MIC) by the broth dilution method and 96 agar dilution method respectively for four different antimicrobial drugs (ceftiofur, gentamicin, florfenicol and doxycycline). The result data were repeated and compared. Results The MICs determined by two methods were identical accounting for 30%~50%, with a difference of one gradients accounting for 80%, and within three gradients, the coincidence rate was as high as 96%. The 96 dot matrix agar dilution method had good repeatability and stability. Conclusion There was no significant difference between the two methods of the broth microdilution method and the 96 broth dilution method on MIC detected, and the same quality control standard could be shared. The standardization and normalization of the 96 dot agar dilution method was conducive to the development of high throughput antimicrobial sensitivity detection, and to promote the establishment of a perfect drug resistance monitoring system.
