Susceptibility to Imipenem/Relebactam of Pseudomonas aeruginosa and Acinetobacter baumannii Isolates from Chinese Intra-Abdominal, Respiratory and Urinary Tract Infections: SMART 2015 to 2018

Figures & data

Table 1 In vitro Activity of Imipenem/Relebactam and Imipenem Against P. Aeruginosa and A. Baumannii Collected in China from 2015 to 2018

Organism/Antimicrobial Agent	MIC (mg/L)			MIC Interpretation
	MIC50	MIC90	MIC Range	Susceptible Rate (%)	Intermediate Rate (%)	Resistant Rate (%)
P. aeruginosa (N = 1886)
Imipenem/relebactam	0.5	8	< 0.6 to > 32	84.2	5.0	10.8
Imipenem	2	32	< 0.12 to > 32	55.7	6.2	38.1
Imipenem-non-susceptible P. aeruginosa (N = 835)
Imipenem/relebactam	2	> 32	0.25 to > 32	64.4	11.1	24.4
Imipenem	16	> 32	4 to > 32	0.0	13.9	86.1
MDR P. aeruginosa (N = 835)
Imipenem/relebactam	2	> 32	< 0.06 to > 32	65.8	10.2	24.1
Imipenem	16	> 32	0.25 to > 32	25.2	6.7	68.1
A. baumannii (N = 1889)
Imipenem/relebactam	32	> 32	< 0.06 to > 32	22.2	0.6	77.2
Imipenem	32	> 32	< 0.12 to > 32	21.0	0.5	78.6
Imipenem-non-susceptible A. baumannii (N = 1493)
Imipenem/relebactam	32	> 32	0.25 to > 32	1.8	0.7	97.5
Imipenem	32	> 32	4 to > 32	0.0	0.6	99.4
MDR A. baumannii (N = 1547)
Imipenem/relebactam	32	> 32	< 0.06 to >32	5.3	0.7	94.1
Imipenem	32	> 32	0.25 to > 32	4.0	0.4	95.6

Abbreviations: MIC, minimum inhibitory concentrations; MDR, multidrug resistance.

Figure 1 Effect of relebactam on MIC distribution of imipenem against: (A) P. aeruginosa isolates (n = 1886); (B) imipenem-non-susceptible P. aeruginosa (n = 835); (C) MDR P. aeruginosa isolates (n = 835). Dashed line represents the FDA identified susceptibility breakpoint of imipenem/relebactam of ≤ 2 mg/mL for P. aeruginosa.

Abbreviations: MIC, minimum inhibitory concentrations; MDR, multidrug resistance.

Figure 2 Comparison of P. aeruginosa strain susceptibilities. From IAIs, UTIs and RTIs isolated (A) total P. aeruginosa, (B) imipenem-non-susceptible P. aeruginosa and (C) MDR P. aeruginosa strain susceptibilities to imipenem/relebactam, and imipenem. From ICUs and non-ICU departments isolated (D) total P. aeruginosa, (E) imipenem-non-susceptible P. aeruginosa and (F) MDR P. aeruginosa strain susceptibilities to imipenem/relebactam, and imipenem.

Abbreviations: IAIs, intra-abdominal infections; ICU, intensive care unit; MDR, multidrug-resistance; RTIs, respiratory tract infections; UTIs, urinary tract infections.

Table 2 In vitro Activity of Imipenem/Relebactam and Imipenem Against P. Aeruginosa Isolates from ICUs and Non-ICU Wards

Organism/Antimicrobial Agent	ICU Origin (IAIs + UTIs + RTIs)				Non-ICU Origin (IAIs + UTIs + RTIs)
	N	S%	R%	MIC90	N	S%	R%	MIC90
P. aeruginosa
Imipenem/relebactam	441	345 (78.2)	72 (16.3)	32	1445	1243 (86.0)	132 (9.1)	4
Imipenem	441	209 (47.4)	208 (47.2)	> 32	1445	842 (58.3)	511 (35.4)	32
Imipenem-non-susceptible P. aeruginosa
Imipenem/relebactam	232	136 (58.6)	72 (31.0)	> 32	603	402 (66.7)	132 (21.9)	32
Imipenem	232	0 (0.0)	208 (89.7)	> 32	603	0 (0.0)	511 (84.7)	> 32
MDR P. aeruginosa
Imipenem/relebactam	229	134 (58.5)	72 (31.4)	> 32	606	415 (68.5)	129 (21.3)	32
Imipenem	229	48 (21.0)	169 (73.8)	> 32	606	162 (26.7)	400 (66.0)	> 32

Abbreviations: IAIs, intra-abdominal infections; ICU, intensive care unit; MDR, multidrug-resistance; MIC, minimum inhibitory concentrations; N, number; R, resistant rate; RTIs, respiratory tract infections; S, susceptible rate; UTIs, urinary tract infections.

Figure 3 Changes in the susceptibility of (A) P. aeruginosa, (B) MDR P. aeruginosa and (C) imipenem-non-susceptible P. aeruginosa to imipenem/relebactam over time in different regions of China (2015, 2016, 2017, 2018). Country map to show the incidence (%) of (D) MDR P. aeruginosa and (E) imipenem-non-susceptible P. aeruginosa in different regions of China from 2015 to 2018.

Abbreviation: MDR, multidrug-resistance.