Integration of functional and molecular approaches based on Bush-Jacoby-Medeiros classification for bacterial b lactamases
 

Functional groups	Molecular classes	Preferred substrate	Inhibited by		Examples of bacteria/enzymes
			CA	EDTA
1	C	Cephalosporins: first, second, third generation	-	-	Enterobacteriacae/AmpC*
2a	A	Penicillins	+	-	K pneumoniae*, P aeruginosa‡, Bacillus sp*, anaerobes§, S aureus‡§
2b	A	Penicillins, cephalosporins	+	-	S paratyphi/ TEM-1‡, P aeruginosa/TEM-2‡, E coli/SHV-1‡, H influenzae/ ROB-1‡
2be	A	Penicillins, oxyimino-cephalosporins, monobactam	+	-	K pneumoniae/SHV(2-6)‡, E coli/TEM (3-26)‡, K oxytoca/K1*
2br	A	Penicillins	±	-	E coli/TEM (30-36)‡, Nocardia brasiliensis‡
2c	A	Penicillins, carbenicillin	+	-	P aeruginosa/CARB (3,4) and PSE-1/3/4‡, Moraxella catarrhalis and Proteus mirabilis/BRO(1-2)§, Vibrio cholerae‡/SAR-1, Acinetobacter sp*/CARB-5
2d	D	Penicillins, cloxacillin	±	-	Enterobacteriacae/OXA(1-12)*‡, Aeromonas spp/OXA-12*, P aeruginosa/OXA (5,6)‡, Bacteroides spp/OXA§
2e	A	Cephalosporins, monobactams	+	-	Proteus spp/FPM-1*†‡§, B fragilis/CepA*‡
2f	A	Penicillins, cephaloporins, carbapenems	+	-	E cloacae/IMI-1†/NMC-A*, Serratia marcescens/Sme-1*
3	B	Penicillins, cephalosporins	-	+	Xanthomonas maltophila/L-1†, P aeruginosa and B fragilis/CcrA‡, B cereus*, A hydrophila/A2h†‡, Serratia marcescens/IMP-1*
4	ND	Penicillins	-	?	P cepacia/SAR-2*, Campylobacter jejuni§, B fragilis*

CA=clavulanic acid; ND=not determined.

*Chromosomal enzyme.

†Inducible enzyme.

‡Plasmid enzyme.

§Enzyme type not determined.