TABLE 1.

In vitro activities of plazomicin and comparator agents against clinical isolates of Gram-negative bacteria

Organism (no. of isolates) and agent	MIC (µg/ml)			% of isolates
	50%	90%	Range	Susceptible	Intermediate	Resistant
Escherichia coli (3,094)
Plazomicin	0.5	1	≤0.12 to >64	99.5	0.4	0.1
Amikacin	2	4	≤1 to >64	99.8	0.1	0.1
Gentamicin	≤0.5	2	≤0.5 to >32	90.9	0.3	8.8
Tobramycin	≤0.5	4	≤0.5 to >64	91.8	2.7	5.5
Cefazolin	2	>128	≤0.5 to >128	70.9	8.8	20.3
Ceftazidime	≤0.25	4	≤0.25 to >32	90.8	1.5	7.7
Ceftriaxone	≤0.25	32	≤0.25 to >64	87.4	0.4	12.2
Ciprofloxacin	≤0.06	>16	≤0.06 to >16	75.3	0.1	24.6
Ertapenem	≤0.03	≤0.03	≤0.03 to >32	99.7	0.1	0.2
Meropenem	≤0.03	≤0.03	≤0.03 to 32	99.9	0	0.1
Piperacillin-tazobactam	2	4	≤1 to >512	97.1	1.5	1.4
Tigecycline	0.25	0.5	≤0.03 to 4	99.9	0.1	0
Trimethoprim-sulfamethoxazole	≤0.12	>8	≤0.12 to >8	73.0	NAa	27.0
Klebsiella pneumoniae (1,039)
Plazomicin	0.25	0.5	≤0.12 to >64	99.8	0.1	0.1
Amikacin	≤1	2	≤1 to >64	99.9	0	0.1
Gentamicin	≤0.5	≤0.5	≤0.5 to >32	95.8	0	4.2
Tobramycin	≤0.5	≤0.5	≤0.5 to >64	94.5	2.6	2.9
Cefazolin	1	16	≤0.5 to >128	82.3	5.3	12.4
Ceftazidime	≤0.25	1	≤0.25 to >32	93.1	0.6	6.3
Ceftriaxone	≤0.25	≤0.25	≤0.25 to >64	91.9	0.1	8.0
Ciprofloxacin	≤0.06	1	≤0.06 to >16	91.6	1.8	6.6
Ertapenem	≤0.03	0.06	≤0.03 to >32	98.6	0.3	1.1
Meropenem	≤0.03	0.06	≤0.03 to 16	99.4	0.2	0.4
Piperacillin-tazobactam	2	8	≤1 to >512	95.6	1.6	2.8
Tigecycline	0.5	1	0.12 to >16	96.2	3.2	0.6
Trimethoprim-sulfamethoxazole	≤0.12	>8	≤0.12 to >8	87.9	NA	12.1
Enterobacter cloacae (470)
Plazomicin	0.25	0.5	≤0.12 to 2	100	0	0
Amikacin	≤1	2	≤1 to 16	100	0	0
Gentamicin	≤0.5	≤0.5	≤0.5 to >32	97.9	0	2.1
Tobramycin	≤0.5	≤0.5	≤0.5 to >64	96.6	1.1	2.3
Cefazolin	>128	>128	1 to >128	1.9	1.7	96.4
Ceftazidime	0.5	>32	≤0.25 to >32	76.0	0.8	23.2
Ceftriaxone	≤0.25	>64	≤0.25 to >64	72.8	2.1	25.1
Ciprofloxacin	≤0.06	0.12	≤0.06 to >16	94.3	1.7	4.0
Ertapenem	0.06	0.5	≤0.03 to >32	91.3	5.1	3.6
Meropenem	≤0.03	0.12	≤0.03 to >32	99.4	0.2	0.4
Piperacillin-tazobactam	2	64	≤1 to >512	85.5	8.3	6.2
Tigecycline	0.5	1	0.12 to 8	95.5	2.4	2.1
Trimethoprim-sulfamethoxazole	≤0.12	1	≤0.12 to >8	91.5	NA	8.5
Klebsiella oxytoca (279)
Plazomicin	0.25	0.5	≤0.12 to 2	100	0	0
Amikacin	≤1	2	≤1 to 8	100	0	0
Gentamicin	≤0.5	≤0.5	≤0.5 to >32	98.6	0.3	1.1
Tobramycin	≤0.5	≤0.5	≤0.5 to 32	99.3	0.3	0.4
Cefazolin	8	>128	≤0.5 to >128	27.6	22.2	50.2
Ceftazidime	≤0.25	0.5	≤0.25 to >32	98.6	0.3	1.1
Ceftriaxone	≤0.25	1	≤0.25 to >64	90.0	2.1	7.9
Ciprofloxacin	≤0.06	≤0.06	≤0.06 to >16	98.9	0.4	0.7
Ertapenem	≤0.03	≤0.03	≤0.03 to 0.12	100	0	0
Meropenem	≤0.03	0.06	≤0.03 to 0.5	100	0	0
Piperacillin-tazobactam	2	32	≤1 to >512	89.6	1.4	9.0
Tigecycline	0.5	0.5	0.12 to 4	99.3	0.7	0
Trimethoprim-sulfamethoxazole	≤0.12	≤0.12	≤0.12 to >8	97.1	NA	2.9
Serratia marcescens (255)
Plazomicin	0.5	1	≤0.12 to 8	97.6	2.0	0.4
Amikacin	2	4	≤1 to 16	100	0	0
Gentamicin	≤0.5	1	≤0.5 to 8	99.6	0.4	0
Tobramycin	1	4	≤0.5 to 64	95.7	2.3	2.0
Cefazolin	>128	>128	128 to >128	0	0	100
Ceftazidime	0.5	1	≤0.25 to >32	99.2	0.4	0.4
Ceftriaxone	≤0.25	1	≤0.25 to >64	93.7	2.0	4.3
Ciprofloxacin	≤0.06	1	≤0.06 to 16	94.1	1.6	4.3
Ertapenem	≤0.03	0.12	≤0.03 to 16	98.0	1.2	0.8
Meropenem	0.06	0.06	≤0.03 to 8	99.2	0.4	0.4
Piperacillin-tazobactam	2	4	≤1 to 256	97.6	1.6	0.8
Tigecycline	2	4	0.5 to 16	88.2	10.2	1.6
Trimethoprim-sulfamethoxazole	0.5	1	≤0.12 to >8	96.9	NA	3.1
Proteus mirabilis (235)
Plazomicin	4	4	0.5 to 32	44.3	46.3	9.4
Amikacin	4	8	≤1 to 32	98.7	1.3	0
Gentamicin	≤0.5	2	≤0.5 to >32	94.5	0.8	4.7
Tobramycin	≤0.5	1	≤0.5 to >64	95.3	1.3	3.4
Cefazolin	4	8	2 to >128	5.1	71.9	23.0
Ceftazidime	≤0.25	≤0.25	≤0.25 to 16	98.3	1.3	0.4
Ceftriaxone	≤0.25	≤0.25	≤0.25 to >64	97.9	0.8	1.3
Ciprofloxacin	≤0.06	2	≤0.06 to >16	88.1	3.0	8.9
Ertapenem	≤0.03	≤0.03	≤0.03 to 1	99.6	0.4	0
Meropenem	0.06	0.12	≤0.03 to 1	100	0	0
Piperacillin-tazobactam	≤1	≤1	≤1 to 64	99.1	0.9	0
Tigecycline	4	8	0.5 to 16	13.6	55.3	31.1
Trimethoprim-sulfamethoxazole	≤0.12	>8	≤0.12 to >8	80.9	NA	19.1
Klebsiella aerogenes (97)
Plazomicin	0.5	0.5	≤0.12 to 2	100	0	0
Amikacin	≤1	2	≤1 to 8	100	0	0
Gentamicin	≤0.5	≤0.5	≤0.5 to 2	100	0	0
Tobramycin	≤0.5	≤0.5	≤0.5 to 16	99.0	0	1.0
Cefazolin	128	>128	1 to >128	3.1	3.1	93.8
Ceftazidime	0.5	>32	≤0.25 to >32	73.2	3.1	23.7
Ceftriaxone	≤0.25	32	≤0.25 to >64	72.2	0	27.8
Ciprofloxacin	≤0.06	0.12	≤0.06 to 8	96.9	1.0	2.1
Ertapenem	0.12	0.5	≤0.03 to >32	93.8	3.1	3.1
Meropenem	0.06	0.06	≤0.03 to 32	99.0	0	1.0
Piperacillin-tazobactam	4	32	≤1 to 256	83.5	14.4	2.1
Tigecycline	0.5	1	0.06 to 4	99.0	1.0	0
Trimethoprim-sulfamethoxazole	≤0.12	0.5	≤0.12 to >8	95.9	NA	4.1
Morganella morganii (54)
Plazomicin	2	4	0.25 to 8	66.7	27.7	5.6
Amikacin	2	4	≤1 to 8	100	0	0
Gentamicin	≤0.5	32	≤0.5 to >32	88.9	0	11.1
Tobramycin	≤0.5	4	≤0.5 to 64	96.3	1.8	1.9
Cefazolin	>128	>128	8 to >128	0	0	100
Ceftazidime	≤0.25	16	≤0.25 to >32	83.3	5.6	11.1
Ceftriaxone	≤0.25	2	≤0.25 to >64	87.0	7.4	5.6
Ciprofloxacin	≤0.06	>16	≤0.06 to >16	83.3	0	16.7
Ertapenem	≤0.03	0.06	≤0.03 to 0.5	100	0	0
Meropenem	0.06	0.12	≤0.03 to 0.5	100	0	0
Piperacillin-tazobactam	≤1	2	≤1 to 256	98.1	0	1.9
Tigecycline	2	4	0.12 to 16	81.5	14.8	3.7
Trimethoprim-sulfamethoxazole	0.25	>8	≤0.12 to >8	83.3	NA	16.7
Pseudomonas aeruginosa (1,789)
Plazomicin	4	16	≤0.12 to >64	NA	NA	NA
Amikacin	4	16	≤1 to >64	94.4	2.2	3.4
Gentamicin	1	8	≤0.5 to >32	89.5	4.4	6.1
Tobramycin	≤0.5	2	≤0.5 to >64	94.2	1.3	4.5
Ceftazidime	4	32	≤0.25 to >32	80.2	7.6	12.2
Ciprofloxacin	0.25	4	≤0.06 to >16	80.3	7.1	12.6
Meropenem	0.5	8	≤0.03 to >32	79.7	6.7	13.6
Piperacillin-tazobactam	4	64	≤1 to >512	83.0	8.7	8.3
Acinetobacter baumannii (68)
Plazomicin	1	8	0.25 to >64	NA	NA	NA
Amikacin	≤1	4	≤1 to >64	98.5	0	1.5
Gentamicin	≤0.5	2	≤0.5 to >32	92.6	1.5	5.9
Tobramycin	≤0.5	1	≤0.5 to >64	97.1	1.4	1.5
Ceftazidime	8	16	1 to >32	77.9	17.7	4.4
Ceftriaxone	16	32	1 to >64	44.1	33.8	22.1
Ciprofloxacin	0.25	0.5	≤0.06 to >16	97.1	0	2.9
Meropenem	0.5	2	0.06 to >32	98.5	0	1.5
Piperacillin-tazobactam	4	32	≤1 to >512	83.8	13.3	2.9
Tigecycline	0.25	2	0.12 to 16	NA	NA	NA
Trimethoprim-sulfamethoxazole	≤0.12	0.5	≤0.12 to >8	94.1	NA	5.9
Stenotrophomonas maltophilia (332)
Plazomicin	>64	>64	≤0.12 to >64	NA	NA	NA
Amikacin	>64	>64	≤1 to >64	NA	NA	NA
Gentamicin	32	>32	≤0.5 to >32	NA	NA	NA
Tobramycin	32	>64	≤0.5 to >64	NA	NA	NA
Ceftazidime	>32	>32	0.5 to >32	22.3	6.9	70.8
Ciprofloxacin	4	16	0.12 to >16	NA	NA	NA
Tigecycline	1	4	0.12 to 16	NA	NA	NA
Trimethoprim-sulfamethoxazole	0.25	1	≤0.12 to >8	97.3	NA	2.7

^aNA, MIC breakpoint not applicable.