Table 3.

Specific activity with 100 μM substrate^a

Antibiotic	Sp act (nmol min−1 mg−1) of β-lactamase:
	GES-14	GES-12	GES-11	GES-1	GES-5
Imipenem	193	42	31	15	1,330
Meropenem	22	17	7	1.5	120
Ertapenem	23	14	5	7	180
Cefoxitin	228	62	45	103	1,400
Cefotaxime	468	12,200	58,900	7,660	290
Ceftazidime	24	9,968	5,345	562	27
Aztreonam	141	6,220	3,248	234	7

^aStandard deviations were within 10% of the means. Values for GES-1 and GES-5 are from Bebrone et al. (unpublished).