Table 1.

Results of strain-tailored DDST applied to a collection of P. aeruginosa strains producing ES-OXAs, ESBLs, or MBLs or overproducing the AmpC cephalosporinase^a

Enzyme produced	Reference strain		No. of additional clinical strains tested	Synergy between disks containingb:
	Reference or accession no.	CAZ MIC (μg/ml)		CLA-FEP	CLA-CAZ	IMP-FEP	IMP-CAZ
OXA-11	13	512	0	+	+	+	+
OXA-14	7	512	1c	−	−	+	+
OXA-15	8	128	0	+	+	−	+
OXA-16	9	≥128	0	+	+	−	+
OXA-17	6	128	0	+	+	+	+
OXA-18	26	128	0	+	+	+	+
OXA-19	24	512	48d	+	+	+	+
OXA-28	29	256	13e	+	+	+	+
OXA-32	28	128	0	−	+	−	+
OXA-142	EU358785	128	0	+	−	+	+
OXA-144	18	>64	0	−	−	−	−
OXA-145	FJ790516	128	0	+	−	+	+
OXA-147	12	256	0	+	−	+	−
OXA-161	17	128	0	−	+	−	+
OXA-183	HQ111474	128	0	+	−	+	−
PER-1	21	512	3f	+	+	+	+
GES-1	11	32	0	+	+	+	+
VEB-1	1	>512	1f	+	+	+	+
BEL-1	27	32	0	+	+	−	+
VIM-1	1	>128	0	−	−	−	−
AmpC	23	32	12g	−	−	−	−

^aCLA, clavulanate (10 μg); CAZ, ceftazidime (30 μg); FEP, cefepime (30 μg); IMP, imipenem (10 μg).

^b+, enlarged zone of inhibition or synergy zone of inhibition; −, no synergy.

^cReference 4.

^dReference 5.

^eReference 13a.

^fReference 15.

^gReference 3.