In vitro selection of aztreonam/avibactam resistance in dual-carbapenemase-producing Klebsiella pneumoniae.

ABSTRACT:

Objectives

To examine the in vitro selection of aztreonam/avibactam resistance among MBL-producing Klebsiella pneumoniae and to understand the mechanism of increased resistance.

Methods

The MICs of aztreonam were determined with and without avibactam (4 mg/L) using a broth microdilution method. Single-step and multi-step mutant selection was conducted on five MBL-producing K. pneumoniae strains, including two dual carbapenemase producers. Genomic sequencing and gene cloning were performed to investigate the mechanism of increased resistance.

Results

We examined the MICs for 68 MBL-producing K. pneumoniae isolates, including 13 dual carbapenemase producers. Compared with aztreonam alone, the addition of avibactam (4 mg/L) reduced the MICs for all isolates by >128-fold,

SUBMITTER: Niu S 

PROVIDER: S-EPMC7021086 | biostudies-literature | 2020 Mar

REPOSITORIES: biostudies-literature