Skip to main content
. 2017 Oct 24;61(11):e01045-17. doi: 10.1128/AAC.01045-17

TABLE 2.

Activity of ceftazidime-avibactam and comparator antimicrobial agents when tested against Enterobacteriaceae, P. aeruginosa, and selected resistant subsetsa

Organism category and antimicrobial agent (no. of isolates tested) MIC (μg/ml)
 CLSIb
 EUCAST
MIC50 MIC90 %S %R %S %R
Enterobacteriaceae
    All isolates (36,380)
        Ceftazidime-avibactam 0.12 0.25 99.9 0.1* 99.9 0.1
        Ceftriaxone ≤0.06 >8 85.3 13.6 85.3 13.6
        Ceftazidime 0.25 8 88.8 9.9 86.2 11.2
        Cefepime ≤0.12 2 91.2 6.7 89.8 7.7
        Piperacillin-tazobactam 2 16 92.7 4.1 89.8 7.3
        Meropenem ≤0.06 ≤0.06 98.5 1.3 98.7 0.7
        Levofloxacin ≤0.12 >4 82.6 15.6 78.7 18.8
        Gentamicin ≤1 2 91.2 7.6 90.2 8.8
        Amikacin 2 4 99.2 0.2 98.4 0.8
        Tigecycline 0.25 1 98.0 0.1* 92.7 2.0
        Colistin ≤0.5 >8 78.2 21.8
    MDR (2,953)c
        Ceftazidime-avibactam 0.25 1 99.2 0.8* 99.2 0.8
        Ceftriaxone >8 >8 19.7 77.2 19.7 77.2
        Ceftazidime 32 >32 29.6 63.9 22.1 70.4
        Cefepime 16 >16 37.4 51.1 32.0 56.8
        Piperacillin-tazobactam 16 >64 52.7 29.8 45.2 47.3
        Meropenem ≤0.06 8 82.2 15.3 84.7 8.9
        Levofloxacin >4 >4 20.6 70.6 11.2 84.8
        Gentamicin >8 >8 38.2 50.8 34.5 61.8
        Amikacin 4 16 91.1 2.2 84.4 8.9
        Tigecycline 0.5 4 88.9 0.3* 76.9 11.1
        Colistin ≤0.5 >8 60.7 39.3
    XDR (448)d
        Ceftazidime-avibactam 0.5 2 97.8 2.2* 97.8 2.2
        Ceftriaxone >8 >8 2.0 97.3 2.0 97.3
        Ceftazidime >32 >32 5.4 91.5 2.9 94.6
        Cefepime >16 >16 10.5 79.9 6.4 85.8
        Piperacillin-tazobactam >64 >64 7.1 83.7 6.5 92.9
        Meropenem 8 >8 21.2 72.5 27.5 48.2
        Levofloxacin >4 >4 8.7 84.8 2.2 96.4
        Gentamicin 8 >8 27.0 50.0 23.4 73.0
        Amikacin 16 32 60.2 9.6 46.5 39.8
        Tigecycline 0.5 4 90.0 0.2* 81.0 10.0
        Colistin ≤0.5 >8 61.3 38.7
    CRE (513)e
        Ceftazidime-avibactam 0.5 2 97.5 2.5* 97.5 2.5
        Ceftriaxone >8 >8 2.1 97.5 2.1 97.5
        Ceftazidime >32 >32 4.3 93.0 2.3 95.7
        Cefepime >16 >16 8.4 77.9 3.2 87.1
        Piperacillin-tazobactam >64 >64 3.1 91.2 2.7 96.9
        Meropenem >8 >8 2.7 89.7 10.3 52.4
        Levofloxacin >4 >4 23.4 72.9 15.0 81.3
        Gentamicin 8 >8 49.5 33.9 44.4 50.5
        Amikacin 8 32 68.2 7.0 51.5 31.8
        Tigecycline 0.5 1 98.8 0.0* 90.3 1.2
        Colistin ≤0.5 >8 79.1 20.9
    Ceftriaxone-nonsusceptible K. pneumoniae (1,063)f
        Ceftazidime-avibactam 0.25 1 99.6 0.4* 99.6 0.4
        Ceftriaxone >8 >8 0.0 97.5 0.0 97.5
        Ceftazidime >32 >32 9.0 84.5 3.4 91.0
        Cefepime >16 >16 12.3 74.4 8.9 81.6
        Piperacillin-tazobactam 32 >64 44.7 44.3 31.8 55.3
        Meropenem ≤0.06 >8 64.2 32.8 67.2 22.3
        Levofloxacin >4 >4 35.1 58.6 24.1 67.9
        Gentamicin 8 >8 46.5 45.3 42.1 53.5
        Amikacin 4 32 81.0 4.2 70.3 19.0
        Tigecycline 0.5 1 98.8 0.0* 91.2 1.2
        Colistin ≤0.5 4 88.9 11.1
    Colistin-nonsusceptible K. pneumoniae (205)
        Ceftazidime-avibactam 0.25 2 99.5 0.5* 99.5 0.5
        Ceftriaxone >8 >8 42.9 55.6 42.9 55.6
        Ceftazidime 32 >32 42.0 57.1 40.0 58.0
        Cefepime 16 >16 46.7 51.1 46.7 51.1
        Piperacillin-tazobactam 16 >64 51.2 45.9 41.0 48.8
        Meropenem ≤0.06 >8 62.4 37.6 62.4 31.2
        Levofloxacin >4 >4 46.8 50.2 42.0 54.1
        Gentamicin ≤1 >8 69.8 25.9 65.9 30.2
        Amikacin 2 32 77.6 7.3 66.8 22.4
        Tigecycline 0.5 2 99.5 0.0* 89.3 0.5
        Colistin >8 >8 0.0 100.0
    Ceftazidime-nonsusceptible (≥8 μg/ml) Enterobacter cloacae (831)g
        Ceftazidime-avibactam 0.5 1 99.3 0.7* 99.3 0.7
        Ceftriaxone >8 >8 0.0 99.4 0.0 99.4
        Ceftazidime >32 >32 0.0 95.8 0.0 100.0
        Cefepime 2 >16 65.1 18.3 43.1 24.1
        Piperacillin-tazobactam 64 >64 23.8 35.9 16.6 76.2
        Meropenem ≤0.06 0.25 93.5 5.1 94.9 1.3
        Levofloxacin ≤0.12 >4 82.3 12.9 75.5 20.6
        Gentamicin ≤1 >8 83.5 12.8 82.2 16.5
        Amikacin 1 4 99.3 0.6 98.0 0.7
        Tigecycline 0.25 2 98.3 0.0* 89.2 1.7
        Colistin ≤0.5 >8 84.6 15.4
P. aeruginosa
    All isolates (7,868)
        Ceftazidime-avibactam 2 4 97.1 2.9* 97.1 2.9
        Ceftazidime 2 32 84.7 10.9 84.7 15.3
        Cefepime 2 16 85.6 5.2 85.6 14.4
        Piperacillin-tazobactam 4 64 81.0 9.4 81.0 19.0
        Meropenem 0.5 8 81.3 12.8 81.3 6.8
        Levofloxacin 0.5 >4 74.5 18.6 65.3 34.7
        Gentamicin 2 8 87.0 8.4 87.0 13.0
        Amikacin 4 8 96.5 1.9 91.8 3.5
        Colistin 1 2 99.6 0.4 99.6 0.4
    MDR (1,562)
        Ceftazidime-avibactam 4 16 86.5 13.5* 86.5 13.5
        Ceftazidime 16 >32 43.6 41.6 43.6 56.4
        Cefepime 16 >16 41.7 23.0 41.7 58.3
        Piperacillin-tazobactam 64 >64 31.2 36.2 31.2 68.8
        Meropenem 8 >8 20.0 58.2 20.0 32.4
        Levofloxacin >4 >4 18.7 65.0 9.5 90.5
        Gentamicin 4 >8 55.4 32.3 55.4 44.6
        Amikacin 8 32 87.1 7.6 73.9 12.9
        Colistin 1 2 99.2 0.8 99.2 0.8
    XDR (717)
        Ceftazidime-avibactam 8 32 75.9 24.1* 75.9 24.1
        Ceftazidime 32 >32 21.5 60.0 21.5 78.5
        Cefepime 16 >16 17.3 38.1 17.3 82.7
        Piperacillin-tazobactam >64 >64 7.7 52.6 7.7 92.3
        Meropenem >8 >8 3.1 79.6 3.1 52.2
        Levofloxacin >4 >4 5.3 78.4 2.2 97.8
        Gentamicin 8 >8 39.6 47.1 39.6 60.4
        Amikacin 8 >32 80.8 11.6 64.2 19.2
        Colistin 1 2 99.3 0.7 99.3 0.7
    Ceftazidime, meropenem, and piperacillin-tazobactam-nonsusceptible (628)
        Ceftazidime-avibactam 8 32 71.8 28.2* 71.8 28.2
        Ceftazidime 32 >32 0.0 76.0 0.0 100.0
        Cefepime 16 >16 18.3 41.9 18.3 81.7
        Piperacillin-tazobactam >64 >64 0.0 65.1 0.0 100.0
        Meropenem >8 >8 0.0 81.2 0.0 50.6
        Levofloxacin >4 >4 21.9 66.2 13.6 86.4
        Gentamicin 4 >8 54.0 37.4 54.0 46.0
        Amikacin 8 >32 83.0 10.7 71.7 17.0
        Colistin 1 2 99.5 0.5 99.5 0.5
a

CLSI and EUCAST criteria are as published previously (33, 34).

b

*, breakpoints from the FDA package insert (17, 35).

c

MDR organisms included the following: Citrobacter freundii (n = 59), C. koseri (n = 1), Enterobacter aerogenes (n = 42), E. cloacae (n = 119), E. cloacae species complex (n = 153), Escherichia coli (n = 797), Hafnia alvei (n = 3), Klebsiella oxytoca (n = 55), K. pneumoniae (n = 793), Morganella morganii (n = 174), Proteus mirabilis (n = 426), P. vulgaris (n = 5), P. vulgaris group (n = 1), Providencia rettgeri (n = 17), P. stuartii (n = 191), Raoultella ornithinolytica (n = 1), Serratia liquefaciens (n = 1), S. marcescens (n = 112), Raoultella sp. (n = 2), and Serratia sp. (n = 1).

d

XDR organisms included the following: Citrobacter freundii (n = 9), Enterobacter aerogenes (n = 1), E. cloacae (n = 44), Escherichia coli (n = 12), Klebsiella oxytoca (n = 8), K. pneumoniae (n = 297), Morganella morganii (n = 17), Proteus mirabilis (n = 19), Providencia stuartii (n = 18), Raoultella ornithinolytica (n = 1), Serratia marcescens (n = 21), and Raoultella sp. (n = 1).

e

The results of the molecular characterization of these isolates are shown in Table 3. CRE organisms included the following: Citrobacter freundii (n = 6), Enterobacter aerogenes (n = 13), E. cloacae (n = 5), E. cloacae species complex (n = 50), Escherichia coli (n = 24), Klebsiella oxytoca (n = 16), K. pneumoniae (n = 368), Proteus mirabilis (n = 4), Providencia stuartii (n = 2), Raoultella ornithinolytica (n = 1), Serratia marcescens (n = 22), and Raoultella sp. (n = 2).

f

According to CLSI criteria; ≥2 μg/ml (33).

g

According to CLSI criteria; ≥8 μg/ml (33).