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Table 1 Classification schemes for bacterial β-lactamases.

From: New treatment options against gram-negative organisms

Bush-Jacoby group (2009) Molecular class (subclass) Distinctive substrate(s) Defining characteristic(s) Representative enzyme(s)
1 C Cephalosporins Greater hydrolysis of cephalosporins than benzylpenicillin; hydrolyzes cephamycins E. coli AmpC, P99, ACT-1, CMY-2, FOX-1, MIR-1
1e C Cephalosporins Increased hydrolysis of ceftazidime and often other oxyimino-β-lactams GC1, CMY-37
2a A Penicillins Greater hydrolysis of benzylpenicillin than cephalosporins PC1
2b A Penicillins, early Similar hydrolysis of benzylpenicillin and cephalosporins TEM-1, TEM-2, SHV-1
2be A Extended-spectrum Increased hydrolysis of oxyimino-β-lactams (cefotaxime, TEM-3, SHV-2, CTX-M-15, PER-1,
   cephalosporins, monobactams ceftazidime, ceftriaxone, cefepime, aztreonam) VEB-1
2br A Penicillins Resistance to clavulanic acid, sulbactam, and tazobactam TEM-30, SHV-10
2ber A Extended-spectrum Increased hydrolysis of oxyimino-β-lactams combined with TEM-50
   cephalosporins, monobactams resistance to clavulanic acid, sulbactam, and tazobactam  
2c A Carbenicillin Increased hydrolysis of carbenicillin PSE-1, CARB-3
2ce A Carbenicillin, cefepime Increased hydrolysis of carbenicillin, cefepime, and cefpirome RTG-4
2d D Cloxacillin Increased hydrolysis of cloxacillin or oxacillin OXA-1, OXA-10
2de D Extended-spectrum cephalosporins Hydrolyzes cloxacillin or oxacillin and oxyimino-β-lactams OXA-11, OXA-15
2df D Carbapenems Hydrolyzes cloxacillin or oxacillin and carbapenems OXA-23, OXA-48
2e A Extended-spectrum cephalosporins Hydrolyzes cephalosporins. Inhibited by clavulanic acid but not aztreonam CepA
2f A Carbapenems Increased hydrolysis of carbapenems, oxyimino-β-lactams, cephamycins KPC-2, IMI-1, SME-1
3a B (B1) Carbapenems Broad-spectrum hydrolysis including carbapenems but not monobactams IMP-1, VIM-1, CcrA, IND-1
  B (B3)    L1, CAU-1, GOB-1, FEZ-1
3b B (B2) Carbapenems Preferential hydrolysis of carbapenems CphA, Sfh-1
NI Unknown    
  1. Adapted from [5].