TABLE 1.

Antibiotic susceptibility profile and resistance mechanisms of the 21 XDR P. aeruginosa isolates^a

Isolate	ST	Acquired β- lactamase(s)	AmpC hyperproduction	OprD deficiency	MIC (mg/liter)
					AMK	ATM	MEM	CST	CZA
04-017	111	OXA-46	Yes	No	4	64	32	2	8
04-025	175		Yes	Yes	4	16	16	1	4
10-023	175		Yes	Yes	4	16	16	2	4
06-014	179	OXA-10	Yes	Yes	8	16	32	2	4
12-003	244		Yes	Yes	8	32	32	2	4
09-011	274		Yes	Yes	128	64	32	1	4
09-007	313		Yes	Yes	8	32	16	2	4
10-017	395		Yes	No	4	32	8	2	4
06-035	455		Yes	No	<2	64	>32	0.5	8
10-019	2221		Yes	Yes	<2	64	32	2	8
06-025	2534		Yes	Yes	<2	64	8	2	8
06-027	2535		Yes	No	8	32	8	2	4
06-001	2536		Yes	Yes	8	64	32	2	8
09-012	175		Yes	Yes	8	64	16	2	8
10-009	111	VIM-2	Yes	Yes	32	>128	>32	4	>32
07-016	175	GES-5	No	Yes	16	16	>32	2	32
12-012	175	VIM-20, OXA-2	No	Yes	16	8	>32	2	32
07-004	235	GES-19, OXA-2	No	Yes	128	128	>32	2	>32
06-042	235	VIM-47	No	No	64	32	>32	2	32
01-008	253	VIM-1	No	Yes	8	4	>32	2	>32
10-021	2533		Yes	Yes	<2	64	32	1	16

^aMICs (mg/liter) of the following antibiotics tested in this study are shown: amikacin (AMK), aztreonam (ATM), meropenem (MEM),colistin (CST), and ceftazidime-avibactam (CZA). CZA-resistant isolates are highlighted in gray.