Meropenem/vaborbactam retains antimicrobial activity against class A and class C β-lactamase-producing
Enterobacterales, especially those producing
ESBL, KPC, and
AmpC determinants. Meropenem/vaborbactam is also active against strains of
Enterobacterales producing other types of class A serine carbapenemases (e.g. SME and NMC-A enzymes). Resistance to meropenem/vaborbactam in KPC-producing Enterobacterales is currently very rare and mostly due to porin inactivation. Meropenem/vaborbactam retains activity also against strains producing KPC mutants that confer resistance to
ceftazidime/avibactam (e.g., KPC-8, KPC-31). The activity of meropenem/vaborbactam against
P. aeruginosa and
A. baumannii was found to be similar to that of meropenem alone. In fact, in these species, meropenem resistance is largely mediated by mechanisms that are not antagonized by vaborbactam (e.g., outer-membrane impermeability, upregulation of efflux systems, and production of class B or class D β-lactamases). No antimicrobial activity has been reported for MBL-producing Gram-negatives and OXA-48-producing
Enterobacterales. ==History==