Detection of OXA-23-producing Proteus mirabilis in Switzerland.

Proteus mirabilis is a Gram-negative bacterium found in the environment and also forms part of the commensal flora in the gastrointestinal tract of both humans and animals. P. mirabilis can cause a wide variety of infections, however it does not harbor any intrinsic β-lactamase genes and as such usually exhibits full susceptibility to β-lactams with the exception of imipenem, to which it is naturally resistant.

In-vitro activity of the novel β-lactam/β-lactamase inhibitor combinations and cefiderocol against carbapenem-resistant Pseudomonas spp. clinical isolates collected in Switzerland in 2022.

To evaluate the in-vitro activity of the novel commercially-available drugs, including meropenem-vaborbactam (MEV), ceftazidime-avibactam (CZA), ceftolozane-tazobactam (C/T), imipenem-relebactam (IPR) as well as cefiderocol (FDC), against carbapenem-resistant Pseudomonas spp. (CRP) isolates. All CRP isolates collected at the Swiss National Reference Laboratory (NARA) over the year 2022 (n = 170) have been included.

In-vitro activity of newly-developed β-lactamase inhibitors avibactam, relebactam and vaborbactam in combination with anti-pseudomonal β-lactam antibiotics against AmpC-overproducing clinical Pseudomonas aeruginosa isolates.

Purpose: Overproduction of the intrinsic chromosomally-encoded AmpC β-lactamase is one of the main mechanisms responsible for broad-spectrum β-lactam resistance in Pseudomonas aeruginosa. Our study aimed to evaluate the in-vitro activity of anti-pseudomonal β-lactam molecules associated with the recently-developed and commercially-available β-lactamase inhibitors, namely avibactam, relebactam and vaborbactam, against P. aeruginosa isolates overproducing their AmpC.

A Selective Culture Medium for Screening Aztreonam-Avibactam Resistance in Enterobacterales and .

Aztreonam/avibactam (ATM/AVI) has been recently approved drug for clinical use in the European Union. The aim of this study was to develop and evaluate a novel selective medium for the isolation of ATM/AVI-resistant strains (Super ATM/AVI selective medium) to help to control their spread. Minimum inhibitory concentrations of ATM/AVI were determined using the broth microdilution method for 77 Gram-negative isolates, including 62 Enterobacterales and 15 .