Table 1.
Antimicrobial Activity of Ceftolozane/Tazobactam Tested Against the Main Organisms and Organism Groups
| Organism/Organism Group (No. of Isolates) | No. and Cumulative % of Isolates Inhibited at MIC (mg/L) of: | MIC50 | MIC90 | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| ≤0.015 | 0.03 | 0.06 | 0.12 | 0.25 | 0.5 | 1 | 2 | 4 | 8 | 16 | 32 | >a | |||
| Pseudomonas aeruginosa (376) | 0 0.0 |
1 0.3 |
1 0.5 |
39 10.9 |
229 71.8 |
51 85.4 |
10 88.0 |
11 91.0 |
5 92.3 |
2 92.8 |
2 93.4 |
25 100.0 |
0.5 | 4 | |
| Ceftazidime-nonsusceptible (>8 mg/L) (74) | 0 0.0 |
4 5.4 |
18 29.7 |
10 43.2 |
10 56.8 |
3 60.8 |
2 63.5 |
2 66.2 |
25 100.0 |
4 | >32 | ||||
| Meropenem-nonsusceptible (>2 mg/L) (94) | 0 0.0 |
2 2.1 |
24 27.7 |
22 51.1 |
6 57.4 |
8 66.0 |
5 71.3 |
1 72.3 |
2 74.5 |
24 100.0 |
1 | >32 | |||
| Piperacillin/tazobactam-nonsusceptible (>16 mg/L) (79) | 0 0.0 |
1 1.3 |
5 7.6 |
27 41.8 |
10 54.4 |
10 67.1 |
5 73.4 |
2 75.9 |
2 78.5 |
17 100.0 |
2 | >32 | |||
| Levofloxacin-nonsusceptible (>1 mg/L) (112) | 0 0.0 |
3 2.7 |
28 27.7 |
32 56.2 |
7 62.5 |
10 71.4 |
5 75.8 |
1 76.8 |
2 78.6 |
24 100.0 |
1 | >32 | |||
| MDR (77) | 0 0.0 |
1 1.3 |
3 5.2 |
21 32.5 |
8 42.9 |
10 55.8 |
5 62.3 |
2 64.9 |
2 67.5 |
25 100.0 |
4 | >32 | |||
| XDR (57) | 0 0.0 |
2 3.5 |
8 17.5 |
6 28.1 |
9 43.9 |
5 52.6 |
1 54.4 |
2 57.9 |
24 100.0 |
8 | >32 | ||||
| Enterobacterales (1662) | 0 0.0 |
2 0.1 |
20 1.3 |
434 27.4 |
552 60.6 |
261 76.4 |
100 82.4 |
73 86.8 |
31 88.6 |
21 89.9 |
19 91.0 |
24 92.5 |
125 100.0 |
0.25 | 16 |
| Non-ESBL-phenotype (721) | 0 0.0 |
2 0.3 |
18 2.8 |
341 50.1 |
305 92.4 |
50 99.3 |
4 99.9 |
1 100.0 |
0.12 | 0.25 | |||||
| Presumptive ESBL-phenotype (590) | 0 0.0 |
36 6.1 |
127 27.6 |
134 50.3 |
69 62.0 |
54 71.2 |
23 75.1 |
8 76.4 |
12 78.5 |
19 81.7 |
108 100.0 |
0.5 | >32 | ||
| Carbapenem-resistant (CRE) (113) | 0 0.0 |
1 0.9 |
2 2.7 |
0 2.7 |
2 4.4 |
3 7.1 |
9 15.0 |
96 100.0 |
>32 | >32 | |||||
| Presumptive ESBL-phenotype non-carbapenem-resistant (CRE) (492) | 0 0.0 |
36 7.3 |
127 33.1 |
134 60.4 |
68 74.2 |
52 84.8 |
23 89.4 |
7 90.9 |
9 92.7 |
10 94.7 |
26 100.0 |
0.5 | 8 | ||
| MDR (431) | 0 0.0 |
5 1.2 |
63 15.8 |
86 35.7 |
43 45.7 |
45 56.1 |
19 60.6 |
11 63.1 |
15 66.6 |
20 71.2 |
124 100.0 |
2 | >32 | ||
| XDR (58) | 0 0.0 |
1 1.7 |
3 6.9 |
1 8.6 |
1 10.3 |
2 13.8 |
3 19.0 |
47 100.0 |
>32 | >32 | |||||
| Escherichia coli (716) | 0 0.0 |
1 0.1 |
12 1.8 |
286 41.8 |
228 73.6 |
105 88.3 |
38 93.6 |
16 95.8 |
6 96.6 |
1 96.8 |
3 97.2 |
4 97.8 |
16 100.0 |
0.25 | 1 |
| Non-ESBL-phenotype (402) | 0 0.0 |
1 0.2 |
12 3.2 |
255 66.7 |
123 97.3 |
10 99.8 |
1 100.0 |
0.12 | 0.25 | ||||||
| Presumptive ESBL-phenotype (314) | 0 0.0 |
31 9.9 |
105 43.3 |
95 73.6 |
37 85.4 |
16 90.4 |
6 92.4 |
1 92.7 |
3 93.6 |
4 94.9 |
16 100.0 |
0.5 | 2 | ||
| Carbapenem-resistant (CRE) (11) | 0 0.0 |
2 18.2 |
9 100.0 |
>32 | >32 | ||||||||||
| Presumptive ESBL-phenotype non-carbapenem-resistant (CRE) (303) | 0 0.0 |
31 10.2 |
105 44.9 |
95 76.2 |
37 88.4 |
16 93.7 |
6 95.7 |
1 96.0 |
3 97.0 |
2 97.7 |
7 100.0 |
0.5 | 2 | ||
| Klebsiella spp. (610) | 0 0.0 |
1 0.2 |
6 1.1 |
100 17.5 |
209 51.8 |
64 62.3 |
39 68.7 |
43 75.7 |
18 78.7 |
12 80.7 |
8 82.0 |
15 84.4 |
95 100.0 |
0.25 | >32 |
| Klebsiella pneumoniae (547) | 0 0.0 |
1 0.2 |
6 1.3 |
91 17.9 |
183 51.4 |
59 62.2 |
31 67.8 |
38 74.8 |
16 77.7 |
7 79.0 |
8 80.4 |
15 83.2 |
92 100.0 |
0.25 | >32 |
| Non-ESBL-phenotype (286) | 0 0.0 |
1 0.3 |
6 2.4 |
86 32.5 |
162 89.2 |
29 99.3 |
1 99.7 |
1 100.0 |
0.25 | 0.5 | |||||
| Presumptive ESBL-phenotype (261) | 0 0.0 |
5 1.9 |
21 10.0 |
30 21.5 |
30 33.0 |
37 47.1 |
16 53.3 |
7 55.9 |
8 59.0 |
15 64.8 |
92 100.0 |
4 | >32 | ||
| Carbapenem-resistant (CRE) (86) | 0 0.0 |
2 2.3 |
0 2.3 |
1 3.5 |
3 7.0 |
7 15.1 |
73 100.0 |
>32 | >32 | ||||||
| Presumptive ESBL-phenotype non-carbapenem-resistant (CRE) (175) | 0 0.0 |
5 2.9 |
21 14.9 |
30 32.0 |
30 49.1 |
35 69.1 |
16 78.3 |
6 81.7 |
5 84.6 |
8 89.1 |
19 100.0 |
2 | >32 | ||
| Klebsiella oxytoca (13) | 0 0.0 |
2 15.4 |
7 69.2 |
1 76.9 |
1 84.6 |
0 84.6 |
0 84.6 |
0 84.6 |
0 84.6 |
0 84.6 |
2 100.0 |
0.25 | >32 | ||
| Klebsiella aerogenes (50) | 0 0.0 |
7 14.0 |
19 52.0 |
4 60.0 |
7 74.0 |
5 84.0 |
2 88.0 |
5 98.0 |
0 98.0 |
0 98.0 |
1 100.0 |
0.25 | 8 | ||
| Enterobacter cloacae species complex (152) | 0 0.0 |
1 0.7 |
22 15.1 |
54 50.7 |
25 67.1 |
5 70.4 |
10 77.0 |
6 80.9 |
6 84.9 |
6 88.8 |
4 91.4 |
13 100.0 |
0.25 | 32 | |
| Ceftazidime-nonsusceptible (>4 mg/L) (65) | 0 0.0 |
4 6.2 |
12 24.6 |
4 30.8 |
10 46.2 |
6 55.4 |
6 64.6 |
6 73.8 |
4 80.0 |
13 100.0 |
4 | >32 | |||
| Citrobacter spp. (50) | 0 0.0 |
20 40.0 |
19 78.0 |
6 90.0 |
1 92.0 |
0 92.0 |
0 92.0 |
2 96.0 |
1 98.0 |
1 100.0 |
0.25 | 0.5 | |||
| Citrobacter koseri (25) | 0 0.0 |
14 56.0 |
8 88.0 |
3 100.0 |
0.12 | 0.5 | |||||||||
| Citrobacter freundii species complex (25) | 0 0.0 |
6 24.0 |
11 68.0 |
3 80.0 |
1 84.0 |
0 84.0 |
0 84.0 |
2 92.0 |
1 96.0 |
1 100.0 |
0.25 | 8 | |||
| Proteus mirabilis (48) | 0 0.0 |
21 43.8 |
20 85.4 |
4 93.8 |
1 95.8 |
1 97.9 |
0 97.9 |
1 100.0 |
0.5 | 1 | |||||
| Non-ESBL-phenotype (33) | 0 0.0 |
20 60.6 |
11 93.9 |
2 100.0 |
0.25 | 0.5 | |||||||||
| Presumptive ESBL-phenotype (15) | 0 0.0 |
1 6.7 |
9 66.7 |
2 80.0 |
1 86.7 |
1 93.3 |
0 93.3 |
1 100.0 |
0.5 | 4 | |||||
| Indole-positive Proteae (25)a | 0 0.0 |
3 12.0 |
13 64.0 |
8 96.0 |
0 96.0 |
1 100.0 |
0.25 | 0.5 | |||||||
| Morganella morganii (16) | 0 0.0 |
1 6.2 |
12 81.2 |
3 100.0 |
0.25 | 0.5 | |||||||||
| Serratia spp. (54) | 0 0.0 |
8 14.8 |
31 72.2 |
12 94.4 |
2 98.1 |
0 98.1 |
0 98.1 |
0 98.1 |
0 98.1 |
1 100.0 |
0.5 | 1 | |||
| Serratia marcescens (53) | 0 0.0 |
8 15.1 |
31 73.6 |
12 96.2 |
1 98.1 |
0 98.1 |
0 98.1 |
0 98.1 |
0 98.1 |
1 100.0 |
0.5 | 1 | |||
Notes: aIndole-positive Proteae include: Morganella morganii (16), Proteus vulgaris group (3), Providencia rettgeri (3), and P. stuartii (3).