. 2000 May;44(5):1387–1390. doi: 10.1128/aac.44.5.1387-1390.2000

TABLE 2.

Apparent contribution of AmpC β-lactamase to MIC

β-Lactam	MIC_wt/ MIC_ampC^a	AmpC β-lactamase
β-Lactam	MIC_wt/ MIC_ampC^a	k_cat (s⁻¹)^b	K_m (μM)^b	Hydrolysis rate^c
Cephalothin	8	250	22	10.9
Cephaloridine	4	152	230	1.6
Cefamandole	4	5.9	20	0.07
Penicillin G	2	65	1.9	19.2
Ampicillin	2	6.5	0.9	2.8
Cefazolin	2	850	1,900	2.05
Cefoxitin	2	0.15	0.22	0.14
Cefuroxime	2	0.15^d	0.15^d	0.07
Cefsulodin	2	0.3	170	0.01
Carbenicillin	1	0.002	0.1	0.002
Ceftazidime	1	0.34	16	0.001
Cloxacillin	1	0.003^d	0.0005^d	0.003
Imipenem	1	0.01^d	0.8^d	0.001

Based on Table 1 data. wt, wild type.

Taken from reference 20.

Calculated rate of hydrolysis by the constitutive level of AmpC lactamase in wild-type cells (20) at the substrate concentration that is expected to inhibit, by 50%, the most susceptible essential penicillin-binding protein (7, 20). The units are picomoles milligram (dry weight)⁻¹ second⁻¹.

Taken from references 8 and 9.