Performance of Four Fosfomycin Susceptibility Testing Methods against an International Collection of Clinical Pseudomonas aeruginosa Isolates.

摘要: Fosfomycin has been shown to have a wide spectrum of activity against multidrug-resistant gram-negative bacteria; however, breakpoints established only for Escherichia coli or Enterobacterales per the Clinical and Laboratory Standards Institute (CLSI) European Committee on Antimicrobial Susceptibility Testing (EUCAST), respectively. Lack additional organism limits clinical use this agent prompted extrapolation these interpretive categories other organisms like Pseudomonas aeruginosa without supporting evidence. Further complicating utility fosfomycin is specified method minimal inhibitory concentration determination, namely agar dilution, which not widely available both labor- time-intensive. We therefore sought determine susceptibility large international collection P. isolates (n = 198) fosfomycin, compare testing agreement rates across four methods: broth microdilution, disk diffusion, Etest. Results were interpreted according CLSI E. with 49.0-85.8% considered susceptible, dependent upon used. Epidemiological cutoff values calculated determined be 256 μg/mL 512 dilution Agreement analyzed using microdilution resulting high essential rate 91.3% between two methods. These results indicate that may reliable stress need aeruginosa-specific breakpoints.