Cefiderocol susceptibility of Achromobacter spp.: study of an accurately identified collection of 230 strains

Ann Clin Microbiol Antimicrob. 2024 Jun 17;23(1):54. doi: 10.1186/s12941-024-00709-z.

Abstract

Background: Achromobacter spp. are opportunistic pathogens, mostly infecting immunocompromised patients and patients with cystic fibrosis (CF) and considered as difficult-to-treat pathogens due to both intrinsic resistance and the possibility of acquired antimicrobial resistance. Species identification remains challenging leading to imprecise descriptions of resistance in each taxon. Cefiderocol is a broad-spectrum siderophore cephalosporin increasingly used in the management of Achromobacter infections for which susceptibility data remain scarce. We aimed to describe the susceptibility to cefiderocol of a collection of Achromobacter strains encompassing different species and isolation sources from CF or non-CF (NCF) patients.

Methods: We studied 230 Achromobacter strains (67 from CF, 163 from NCF patients) identified by nrdA gene-based analysis, with available susceptibility data for piperacillin-tazobactam, meropenem and trimethoprim-sulfamethoxazole. Minimal inhibitory concentrations (MICs) of cefiderocol were determined using the broth microdilution reference method according to EUCAST guidelines.

Results: Strains belonged to 15 species. A. xylosoxidans represented the main species (71.3%). MICs ranged from ≤ 0.015 to 16 mg/L with MIC50/90 of ≤ 0.015/0.5 mg/L overall and 0.125/2 mg/L against 27 (11.7%) meropenem-non-susceptible strains. Cefiderocol MICs were not related to CF/NCF origin or species although A. xylosoxidans MICs were statistically lower than those of other species considered as a whole. Considering the EUCAST non-species related breakpoint (2 mg/L), 228 strains (99.1%) were susceptible to cefiderocol. The two cefiderocol-resistant strains (A. xylosoxidans from CF patients) represented 3.7% of meropenem-non-susceptible strains and 12.5% of MDR strains.

Conclusions: Cefiderocol exhibited excellent in vitro activity against a large collection of accurately identified Achromobacter strains, irrespective of species and origin.

Keywords: Achromobacter; Cefiderocol; Cystic fibrosis; Opportunistic pathogen; Susceptibility.

MeSH terms

  • Achromobacter* / classification
  • Achromobacter* / drug effects
  • Achromobacter* / genetics
  • Achromobacter* / isolation & purification
  • Anti-Bacterial Agents* / pharmacology
  • Cefiderocol*
  • Cephalosporins* / pharmacology
  • Cystic Fibrosis* / microbiology
  • Gram-Negative Bacterial Infections* / microbiology
  • Humans
  • Microbial Sensitivity Tests*

Substances

  • Anti-Bacterial Agents
  • Cephalosporins
  • Cefiderocol