Meropenem/vaborbactam resistance in Klebsiella pneumoniae is associated with loss of function mutations in the OmpK35 and OmpK36 porins. Here we identify two previously unknown loss of function mutations that confer cefuroxime resistance in K. pneumoniae. The proteins lost were NlpD and KvrA; the latter is a transcriptional repressor controlling capsule production. We demonstrate that KvrA loss reduces OmpK35 and OmpK36 porin production, which confers reduced susceptibility to meropenem/vaborbactam in a KPC-3 producing K. pneumoniae isolate.
Dulyayangkul, P., Wan Ahmad Kamil, W. N. I., Douglas, E. J. A., & Avison, M. B. (Accepted/In press). Mutation of kvrA causes OmpK35/36 porin downregulation and reduced meropenem/vaborbactam susceptibility in KPC-producing Klebsiella pneumoniae. Antimicrobial Agents and Chemotherapy. https://doi.org/10.1128/AAC.02208-19