Activity of ceftolozane/tazobactam against Gram-negative isolates from patients with lower respiratory tract infections – SMART United States 2018–2019

Table 2 Susceptibility of phenotypic subsets of lower respiratory tract infection isolates of P. aeruginosa and Enterobacterales to C/T and comparator agents^a,b – SMART 2018–2019, United States

Species/phenotype	n	% Susceptible
Species/phenotype	n	C/T	P/T	FEP	CAZ	CRO	ATM	MEM	IMI	LVX	AMK
P. aeruginosa
FEP-nonsusceptible	257	82.1	12.5	0	18.3	NA	9.3	38.9	35.4	31.1	86.4
CAZ-nonsusceptible	266	81.6	10.2	21.1	0	NA	12.8	46.6	41.0	38.4	88.7
MEM-nonsusceptible	312	87.8	41.7	49.7	54.5	NA	31.1	0	7.1	30.1	90.1
P/T-nonsusceptible	317	86.8	0	29.0	24.6	NA	12.3	42.6	40.4	36.0	91.2
MDR	181	76.2	8.8	12.7	17.1	NA	3.9	17.7	15.5	17.7	82.3
Enterobacterales
FEP-nonsusceptible	204	59.3	50.5	0	10.3	2.0	9.3	84.8	78.4	31.4	91.7
CAZ-nonsusceptible	321	52.7	43.9	43.0	0	3.7	11.2	89.4	81.9	52.0	95.0
MEM-nonsusceptible	39	12.8	10.3	20.5	12.8	7.7	7.7	0	0	38.5	84.6
P/T-nonsusceptible	232	36.2	0	56.5	22.4	16.4	22.8	84.9	80.2	66.4	94.0
MDR	238	49.6	42.9	30.7	8.8	7.1	9.2	84.9	73.1	36.6	92.4
K. pneumoniae^c
FEP-nonsusceptible	77	63.6	49.4	0	3.9	2.6	5.2	80.5	79.2	28.6	90.9
CAZ-nonsusceptible	87	63.2	47.1	14.9	0	8.1	11.5	82.8	80.5	33.3	92.0
P/T-nonsusceptible	57	45.6	0	31.6	19.3	29.8	31.6	73.7	70.2	47.4	87.7
ESBL screen-positive^d	85	67.1	52.9	11.8	5.9	0	9.4	82.4	80.0	32.9	91.8
MDR	66	59.1	45.5	1.5	0	0	0	77.3	75.8	25.8	89.4
E. coli^c
FEP-nonsusceptible	55	87.3	80.0	0	12.7	0	12.7	98.2	98.2	14.6	92.7
CAZ-nonsusceptible	64	84.4	75.0	25.0	0	3.1	6.3	98.4	98.4	29.7	95.3
P/T-nonsusceptible	29	69.0	0	62.1	44.8	48.3	51.7	96.6	96.6	51.7	93.1
ESBL screen-positive^d	74	86.5	79.7	25.7	16.2	0	16.2	98.7	98.7	25.7	94.6
MDR	45	82.2	73.3	4.4	0	0	2.2	97.8	97.8	11.1	93.3
P. aeruginosa + Enterobacterales
FEP-nonsusceptible	461	72.0	29.3	0	14.7	NA	9.3	59.2	54.4	31.2	88.7
CAZ-nonsusceptible	587	65.8	28.6	33.0	0	NA	11.9	70.0	63.4	45.8	92.2
MEM-nonsusceptible	351	79.5	38.2	46.4	49.9	NA	28.5	0	6.3	31.1	89.5
P/T-nonsusceptible	549	65.4	0	40.6	23.7	NA	16.8	60.5	57.2	48.8	92.4
MDR	419	61.1	28.2	22.9	12.4	NA	6.9	55.8	48.2	28.4	88.1

^a Abbreviations: C/T, ceftolozane/tazobactam; P/T, piperacillin/tazobactam; FEP, cefepime; CAZ, ceftazidime; CRO, ceftriaxone; ATM, aztreonam; MEM, meropenem; IMI, impenem; LVX, levofloxacin; AMK, amikacin; NA, not available
^b Table does not show results for colistin because P. aeruginosa and Enterobacterales cannot be categorized as susceptible to colistin using CLSI M100 (2020) MIC breakpoint criteria
^c MEM-nonsusceptible E. coli (n = 1) and MEM- nonsusceptible K. pneumoniae (n = 15) were not included in the table because there were too few isolates
^d ESBL screen-positive isolates of K. pneumoniae and E. coli were identified by a CRO-nonsusceptible phenotype

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