In an effort to study on the antibiotic resistance in bacteria, we first report the thermokinetic parameters of the imipenem hydrolysis with B1 subclasses metallo-beta-lactamase CcrA from Bacteroides fragilis. The values of activation free energy Delta G(not equal)(theta) is 87.54 +/- 0.03,88.78 +/- 0.03,89.90 +/- 0.04 and 91.06 +/- 0.02kJ mol(-1) at 293.15,298.15,303.15 and 308.15 K, respectively, the activation enthalpy Delta H-not equal(theta) is 19.10 +/- 0.01 kJ mol(-1), the activation entropy Delta S-not equal(theta) is -233.56 +/- 0.09J mol(-1) K-1 and the apparent activation energy E is 21.598 kJ mol(-1). The results reveal that the imipenem hydrolysis catalyzed by CcrA is an exothermic and spontaneous reaction with reaction order of 1.4, and has a lower Delta H-not equal(theta), and Delta S-not equal(theta), than the cefazolin hydrolysis with same enzyme. (C) 2012 Elsevier B.V. All rights reserved.