Therapeutic options for the treatment of infections owing to multidrug-resistant Gram-negative pathogens are often limited. Cefiderocol is a novel siderophore cephalosporin with activity against Gram-negative pathogens, including many multidrug-resistant strains. The activity of cefiderocol was examined against
Enterobacterales
,
Pseudomonas aeruginosa
, and
Acinetobacter baumannii
that included (1) a recent surveillance collection of clinical isolates, (2) a collection of carbapenem-resistant isolates from a previous surveillance study, and (3) a collection of well-characterized isolates. Susceptibility testing for cefiderocol was performed with iron-depleted cation-adjusted Mueller–Hinton broth. Cefiderocol minimum inhibitory concentrations (MICs) were correlated with resistance mechanisms in the well-characterized isolates. For the
Enterobacterales
, including a collection of KPC-possessing
Klebsiella pneumoniae
, cefiderocol MICs were all ≤4 mg/L. Cefiderocol MICs were two- to fourfold higher in cephalosporin-resistant isolates. For
K. pneumoniae
, MICs did not correlate with expression of genes encoding porins or efflux systems. For
P. aeruginosa
, >99% of isolates were inhibited by ≤4 mg/L, including the collection of carbapenem-resistant isolates. For
P. aeruginosa
, cefiderocol activity was not affected by expression of
ampC
,
oprD
, or several efflux systems. All the surveillance isolates of
A. baumannii
, and 88% of the collection of carbapenem-resistant isolates, had cefiderocol MICs ≤4 mg/L. MICs were twofold higher in
A. baummannii
isolates with proven extended-spectrum beta-lactamases, and cefiderocol activity did not correlate with expression of efflux systems. Cefiderocol demonstrated potent activity against important nosocomial pathogens. Continued development of this agent as a therapeutic option against multidrug-resistant bacteria should be encouraged.
Delafloxacin is an option for infections due to methicillin-resistant Staphylococcus aureus. In 2017, 22% of isolates from 7 hospitals in Brooklyn, New York, were nonsusceptible to delafloxacin. Isolates belonging to ST105, a strain associated with healthcare-related infections, predominated. Resistance was also found in ST8, a strain (USA300) associated with community-associated infections.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.