TABLE 2.

Major families of β-lactamases of clinical importance

Enzyme familyaFunctional group or subgroupNo. of enzymesb,cRepresentative enzymes
CMY1, 1e50CMY-1 to CMY-50
TEM2b, 2be, 2br, 2ber172
2b12TEM-1, TEM-2, TEM-13
2be79TEM-3, TEM-10, TEM-26
2br36TEM-30 (IRT-2), TEM-31 (IRT-1), TEM-163
2ber9TEM-50 (CMT-1), TEM-158 (CMT-9)
SHV2b, 2be, 2br127
2b30SHV-1, SHV-11, SHV-89
2be37SHV-2, SHV-3, SHV-115
2br5SHV-10, SHV-72
CTX-M2be90CTX-M-1, CTX-M-44 (Toho-1) to CTX-M-92
PER2be5PER-1 to PER-5
VEB2be7VEB-1 to VEB-7
GES2f15dGES-2 to GES-7 (IBC-1) to GES-15
KPC2f9KPC-2 to KPC-10
SME2f3SME-1, SME-2, SME-3
OXA2d, 2de, 2df158
2d5OXA-1, OXA-2, OXA-10
2de9OXA-11, OXA-14, OXA-15
2df48eOXA-23 (ARI-1), OXA-51, OXA-58
IMP3a26IMP-1 to IMP-26
VIM3a23VIM-1 to VIM-23
IND3a8IND-1, IND-2, IND-2a, IND-3 to IND-7
  • a Enzyme families include those for which numbers have been assigned based on primary amino acid structures (G. Jacoby and K. Bush, http://www.lahey.org/Studies/).

  • b Compiled through December 2009.

  • c The sum of the subgroups in each family does not always equal the total number of enzymes in each family, because some enzyme numbers have been withdrawn, and some enzymes have not been assigned a functional designation by the investigators who provided the amino acid sequence.

  • d GES-1, unlike other members of the GES family, has little detectable interaction with imipenem (49).

  • e Nine clusters of OXA carbapenemases with their individual members have been designated in Table 6 in reference 52.