In vitro activity of cefiderocol against Gram-negative bacterial pathogens in Germany

Widespread antimicrobial resistance in Gram-negative bacteria (GNB), particularly carbapenem resistance, represents a major clinical challenge. Cefiderocol is a novel siderophore cephalosporin active against all carbapenemase classes.

We evaluated the in vitro activity of cefiderocol and other antibacterial agents (ceftazidime/avibactam, ceftolozane/tazobactam, colistin and meropenem) against GNB isolates collected in Germany (2013-2018) as part of two multinational studies. Antimicrobial susceptibility testing was performed by broth microdilution. Minimum inhibitory concentrations were interpreted according to EUCAST breakpoints.

Cefiderocol had high activity against GNB isolates (N = 2298), encompassing both Enterobacterales (n = 1562) and non-fermenter species (n = 736), and maintained high activity against carbapenem-resistant strains (n = 211). The activity of cefiderocol against Enterobacterales was equivalent to that of ceftazidime/avibactam and colistin, while ceftolozane/tazobactam was somewhat less active. Against non-fermenter species, cefiderocol displayed equivalent activity to colistin; both of these agents were more active than ceftazidime/avibactam and ceftolozane/tazobactam. Colistin had similar activity to cefiderocol against the majority of species. These patterns of activity were echoed in carbapenem-resistant isolates. The high activity of cefiderocol was independent of infection site, whereas other antibacterial agents demonstrated slightly lower activity against isolates causing pneumonia compared with those from other key infection sites.

Cefiderocol exhibited consistently high in vitro activity against a variety of GNB isolates collected in Germany, including resistant phenotypes, across multiple infection sites. These data suggest that cefiderocol is an effective choice of antibacterial agent in patients with GNB infection, regardless of species and resistance phenotype to other agents.