Assessment of sustained efficacy and resistance emergence under human-simulated exposure of cefiderocol against using chemostat and murine infection models.

Objectives: This study evaluated the sustained kill and potential for resistance development of exposed to human-simulated exposure of cefiderocol over 72 h in and infection models.

Methods: Seven isolates with cefiderocol MICs of 0.12-2 mg/L were tested.

strains possessing a four amino acid YRIN insertion in PBP3 identified as part of the SIDERO-WT-2014 surveillance study.

Background: In addition to carbapenemases, dissemination of recently reported lineages possessing a four amino acid insertion in PBP3 (encoded by ) that confers reduced susceptibility to PBP3-targeted β-lactams, such as ceftazidime, can pose a threat of antimicrobial resistance.

Objectives: To evaluate genotypic and phenotypic characteristics of possessing the mutated PBP3 collected during SIDERO-WT-2014 surveillance.

Methods: A subset of 65 clinical isolates with MICs ≥2 mg/L for ceftazidime/avibactam, ceftolozane/tazobactam or cefiderocol, among a total of 1529 isolates from the multinational surveillance study, were subjected to gene analysis and antimicrobial susceptibility testing.

Reduced susceptibility mechanism to cefiderocol, a siderophore cephalosporin, among clinical isolates from a global surveillance programme (SIDERO-WT-2014).

Objective: To investigate possible mechanistic factors to explain cefiderocol (CFDC) non-susceptibility, we characterized 38 clinical isolates with a CFDC minimum inhibitory concentration (MIC) of >4μg/mL from a multi-national surveillance study.

Methods: The MIC measurement in the presence of β-lactamase inhibitors and whole genome sequencing were performed.

Results: The MIC decrease of CFDC by β-lactamase inhibitors was observed against all of the test isolates.