Antibiotic susceptibility test based on the dielectrophoretic behavior of elongated Escherichia coli with cephalexin treatment

This study reports the use of dielectrophoresis (DEP), which determined the crossover frequency (cof) of antibiotic-induced elongation of Escherichia coli (E.coli) with regard to the rapid antibiotic susceptibility test (AST). Different dielectric properties and elongation rates of E. coli are caused by various concentrations of cephalexin treatment. According to the authors' results, significant changes in the cof of bacteria treated with 32 mu g/ml antibiotic for 60 min can be found by using a quadruple electrode array, and the results of DEP-based AST correspond with that of agar dilution method. Utilizing this approach could greatly reduce the period of bacteria growth, and obtain the minimum inhibition concentration of E. coli to cephalexin. (C) 2011 American Institute of Physics.[doi:10.1063/1.3600650]