ESBLs: A Clear and Present Danger?

Table 1

Bush-Jacoby-Medeiros Group	Molecular class (Ambler)	Preferred substrates	Representative enzymes	Resistance or susceptibility to β-lactamase inhibitors
1	C	Cephalosporins	AmpC	Resistant
2b	A	Penicillins, Cephalosporins	TEM, SHV	Susceptible
2be	A	Penicillins, extended-spectrum cephalosporins, monobactams	TEM, SHV	Susceptible
2d	D	Penicillins, cloxacillin	OXA	Resistant
2e	A	Cephalosporins	Inducible cephalosporinases from Proteus vulgaris	Susceptible
2f	A	Penicillins, cephalosporins, carbapenems	NMC-A from Enterobacter cloacae	Resistant
3	B	Most β-lactams including carbapenems	L1 from Stenotrophomonas maltophilia	Resistant

Amended from original Bush-Jacoby-Medeiros classification scheme for bacterial β-lactamases.