TABLE 2

MIC distribution for meropenem alone and combined with vaborbactam at a fixed concentration of 8 μg/ml against most common Enterobacteriaceae species producing serine carbapenemases

Organism (no. of strains) and antimicrobial agent(s)No. (cumulative %) of strains with indicated MIC (μg/ml)bMIC (μg/ml)
≤0.060.120.250.51248163264>6450%90%
KPC-producing K. pneumoniae (208)
    Meropenem1 (0.5)4 (2.4)16 (10.1)28 (23.6)60 (52.4)30 (66.8)20 (76.4)49 (100.0)16>64
    Meropenem-vaborbactama136 (65.4)11 (70.7)15 (77.9)20 (87.5)12 (93.3)5 (95.7)2 (96.6)0 (96.6)6 (99.5)0 (99.5)0 (99.5)1 (100.0)≤0.061
E. cloacae (39)
    Meropenem1 (2.6)3 (10.3)9 (33.3)11 (61.5)10 (87.2)2 (92.3)1 (94.9)2 (100.0)832
    Meropenem-vaborbactama28 (71.8)6 (87.2)2 (92.3)0 (92.3)0 (92.3)2 (97.4)1 (100.0)≤0.060.25
KPC-producing E. coli (21)
    Meropenem1 (4.8)3 (19.0)4 (38.1)4 (57.1)8 (95.2)1 (100.0)48
    Meropenem-vaborbactama21 (100.0)≤0.06≤0.06
KPC-producing K. oxytoca (14)
    Meropenem3 (21.4)6 (64.3)0 (64.3)3 (85.7)1 (92.9)0 (92.9)1 (100.0)432
    Meropenem-vaborbactama12 (85.7)0 (85.7)0 (85.7)1 (92.9)0 (92.9)1 (100.0)≤0.060.5
KPC-producing C. freundii (12)
    Meropenem1 (8.3)1 (16.7)5 (58.3)5 (100.0)48
    Meropenem-vaborbactama9 (75.0)2 (91.7)1 (100.0)≤0.060.12
Isolates carrying multiple β-lactamases (75)
    Meropenem1 (1.3)6 (9.3)9 (21.3)21 (49.3)10 (62.7)9 (74.7)19 (100.0)32>64
    Meropenem-vaborbactama49 (65.3)4 (70.7)7 (80.0)6 (88.0)6 (96.0)2 (98.7)0 (98.7)0 (98.7)1 (100.0)≤0.061
  • a Meropenem combined with vaborbactam at a fixed concentration of 8 μg/ml.

  • b —, dilution not tested or no isolates displaying MIC values at this concentration.