Evolution of TEM-related extended-spectrum β-lactamases in Korea

TEM-52, differing from TEM-1 by having the substitutions Glu-104 --> Lys, Met-182 --> Thr, and Gly-238 --> Ser, has previously been described as the most prevalent extended-spectrum beta -lactamase (ESBL) in Korea. In a further survey, we discovered the ESBLs TEM-15, which is like TEM-52 but lacks the substitution at residue 182, and TEM-88, which is like TEM-52 with an additional Gly-196 --> Asp substitution. TEM-88 retained the activity of TEM-52 against moxalactam. Otherwise, the kinetic properties of the three ESBLs failed to show an advantage to this evolution.