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. 2021 May 6;76(8):2071–2078. doi: 10.1093/jac/dkab141

Table 2.

Susceptibility of imipenem-non-susceptible bacteria with different genotypes and phenotypes to β-lactams with and without novel BLI-BLEs

Species with different genotypes and phenotypes N Susceptible (%)
FEPa FPZ CAZ CZA IPM IMR MEM MEV
E. coli and K. pneumoniae 180 23.3 99.4 3.3 88.9 0 75.6 30 82.8
 genotype
  with carbapenemase gene 92 5.4 100 2.2 82.6 0 59.8 7.6 70.7
   with class B carbapenemase gene 13 0 100 0 0 0 0 7.7 53.8
   with blaKPC-like only 58 0 100 0 96.6 0 84.5 0 75.9
   with blaOXA-48-like only 20 25 100 10 95 0 30 30 70
  without carbapenemase gene 88 42 98.9 4.5 95.5 0 92 53.4 95.5
   with ESBL genea only 1 0 100 100 100 0 100 100 100
   with AmpC gene only 41 85.4 97.6 2.4 95.1 0 95.1 63.4 95.1
   with ESBL and AmpC geneb 43 0 100 0 95.3 0 90.7 41.9 95.3
 phenotypec
  class B carbapenemase producerd 11 0 100 0 0 0 0 9.1 45.5
  non-MBL producer 82 7.3 100 2.4 93.9 0 68.3 8.5 74.4
  non-carbapenemase producer 87 41.4 98.9 4.6 95.4 0 92 52.9 95.4
   ESBL producer 22 4.5 100 4.5 100 0 100 72.7 100
A. baumannii 136 1.5 8.1 2.2 1.5 0 0.7 0 0
 genotype
  with class D carbapenemase gene 135 1.5 8.1 2.2 1.5 0 0 0 0
   blaOXA-23-like 117 0 6.8 1.7 0.9 0 0 0 0
   blaOXA-24-like 22 4.5 13.6 0 4.5 0 0 0 0
P. aeruginosa 81 45.7 91.4 43.2 81.5 0 85.2 28.4 42.0
 genotype
  with class B carbapenemase gene 4 0 75 0 0 0 0 0 0
  without carbapenemase gene 77 48.1 92.2 45.5 85.7 0 89.6 29.9 44.2

FEP, cefepime; FPZ, cefepime/zidebactam; CAZ, ceftazidime; CZA, ceftazidime/avibactam; IPM; imipenem; IMR, imipenem/relebactam; MEM, meropenem; MEV, meropenem/vaborbactam.

a

SDD and susceptible breakpoints (≤8 mg/L) for cefepime were used here.

b

Only prevalent ESBL genes were tested.

c

Isolates with positive mCIM and eCIM were defined as class B carbapenemase (MBL) producers; those with positive mCIM but negative eCIM were non-MBL carbapenemase producers; those with negative mCIM were non-carbapenemase producers.

d

Seven of the 18 isolates positive for both eCIM and mCIM were only positive for blaKPC-like by PCR, which was further confirmed by WGS. Therefore, these seven isolates were categorized as non-MBL carbapenemase producers.