Evaluation of the ceftazidime/avibactam and meropenem susceptibility by MALDI-TOF MS directly from positive blood cultures

Eur J Clin Microbiol Infect Dis. 2024 Jan;43(1):171-175. doi: 10.1007/s10096-023-04696-5. Epub 2023 Nov 7.

Abstract

The purpose of this study was to evaluate the MBT-ASTRA to determine susceptibility to ceftazidime/avibactam (CZA) and meropenem (MEM) of Enterobacterales directly from positive blood cultures (BC). Bacterial suspension was incubated with antibiotic and analyzed by MALDI-TOF MS. The relative growth was calculated and cutoff values were determined to categorize isolates as "S," "I," and "R." Klebsiella spp. with CZA 20/8 mg/L and 1.5-h incubation presented 1 (5.9%) major discrepancy and 96.3% category agreement; other species required 2.5 h for 100% category agreement. For MEM, 4 mg/L and 1.5h were necessary, demonstrating 2 (6.67%) minor discrepancies and 93.3% categorical agreement.

Keywords: Antimicrobial susceptibility testing; Blood culture; Ceftazidime/avibactam; MALDI-TOF MS; Meropenem.

MeSH terms

  • Anti-Bacterial Agents / pharmacology
  • Blood Culture*
  • Ceftazidime* / pharmacology
  • Drug Combinations
  • Humans
  • Meropenem / pharmacology
  • Microbial Sensitivity Tests
  • Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
  • beta-Lactamases

Substances

  • Ceftazidime
  • Meropenem
  • avibactam
  • Anti-Bacterial Agents
  • Drug Combinations
  • beta-Lactamases