TABLE 3.

Occurrence of β-lactamase genes in carbapenem-nonsusceptible P. aeruginosa isolates, stratified by phenotype^a

Parameter, phenotype, and β-lactamase content	Enzyme type	Total no. of isolates	No. of isolates that were:
			CAZ-NS	CAZ-NS, CAZ-AVI-S	CAZ-NS, CAZ-AVI-R
Total tested		7,062	1,627	1,064	563
Carbapenem NSb		2,840	1,257	709	548
MBL positive, with or without serine β-lactamase genes	VIM ± TEM-OSBL	252	244	6	238
	VIM + VEB	6	6		6
	VIM + PER	5	5		5
	VIM + SHV	4	4	1	3
	VIM + GES ESBL-like	1	1		1
	VIM + KPC	1	1		1
	IMP ± TEM-OSBL	34	34		34
	NDM	1	1		1
	NDM + VEB	2	2		2
KPC positive, MBL negative	KPC	28	28	22	6
GES positive, MBL negative	GES carbapenemase	48	39	38	1
	GES carbapenemase + GES ESBL-like	16	16	2	14
	GES ESBL-like	20	20	8	12
	GES spectrum undefined	1	1		1
ESBL positive, MBL negative	VEB ± TEM-OSBL	25	25		25
	PER ± TEM-OSBL	23	22	9	13
	SHV	2	2	1	1
OSBL positive, MBL negative	TEM-OSBL	11	7	7
No acquired bla detectedc		2,360	799	615	184
Carbapenem S (not characterized)		4,222	370	355	15

^aCAZ, ceftazidime; CAZ-AVI, ceftazidime-avibactam; S, susceptible; NS, nonsusceptible; R, resistant.

^bIsolates nonsusceptible to meropenem, imipenem, or doripenem were screened for β-lactamase (bla) genes.

^cIsolates are presumed to contain the chromosomal ampC gene common to P. aeruginosa.