FIG 3.

(A) The imipenem degradation rates of the in vitro-synthesized NDM variants (bla_NDM-2, _-3, _-4, _-5, and _-6 and bla_NDM-K211E) and the NDM-1 proteins from the positive clinical isolates in relation to the imipenem degradation rate of the wild-type positive control (A. baumannii strain 65). Data are the averages of three replicate experiments. Error bars show the ±SD. ABA, A. baumannii; KOE, Klebsiella ozaenae; Kpn, Klebsiella pneumoniae; Eco, E. coli. -(%A₀)/min, percentage of absorbance decrease per minute. The horizontal lines represent the cutoff values for judging functional variants, which equal the -(%A₀)/min value of the wild-type NDM-1 control plus 3 × SD (upper line) and minus 3 × SD (lower line). (B) EDTA inhibition assay for the activity of the in vitro-synthesized NDM-1. %A₀, percentage of absorbance relative to the absorbance at time zero (just after imipenem is added).