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

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

Species/phenotype n % Susceptible
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. pneumoniaec
 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-positived 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. colic
 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-positived 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
  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
  2. 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
  3. 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
  4. d ESBL screen-positive isolates of K. pneumoniae and E. coli were identified by a CRO-nonsusceptible phenotype