Impact of the inoculum size on the <i>in vivo</i> activity of the aztreonam-avibactam combination in a murine model of peritonitis due to <i>Escherichia coli</i> expressing CTX-M-15 and NDM-1.

ABSTRACT: The combination of aztreonam (ATM) and avibactam (AVI) is an attractive option to treat infections caused by extended spectrum β-lactamase plus NDM-1-producing Enterobacteriaceae. Since ATM activity was shown to be severely impacted by an increase in the inoculum size in vitro, we wondered whether ATM-AVI activity could be impaired in high-inoculum infections. We analyzed the impact of the inoculum size on ATM-AVI activity in vitro and in a murine model of peritonitis due to susceptible Escherichia coli CFT073-pTOPO and its isogenic derivatives producing NDM-1 (E. coli CFT073-NDM1) and CTX-M-15 plus NDM-1 (E. coli CFT073-CTXM15-NDM1). The impact of the inoculum size on bacterial morphology was studied by microscopic examination. In vitro, at

SUBMITTER: Amoura A 

PROVIDER: S-EPMC11823674 | biostudies-literature | 2025 Feb

REPOSITORIES: biostudies-literature