The lack of internationally approved breakpoint and a handy susceptibility testing reduces fosfomycin usefulness against Pseudomonas aeruginosa. Previous works defined low or moderate agreement between commercial methods and the reference method (agar dilution [AD]). In particular, data lack about testing against P. aeruginosa. We compared disk diffusion (DD), E-test (ET), and automated broth microdilution (BMD) to AD by testing 150 P. aeruginosa isolates. We obtained better categorical agreement (CA) for DD and ET for minimal inhibitory concentration >128 mg/L (84.7% and 92.7%, respectively), but with high very major error (VME). BMD had the lowest VME rate (2/42), but with 64% CA and 52/108 major errors. We cannot define a method comparable to AD. Larger studies, as well as the definition of a breakpoint value are needed for fosfomycin against P. aeruginosa.

Comparison of Three Different Commercial Methods for Fosfomycin Susceptibility Testing in Pseudomonas aeruginosa

Peradotto, Marco;Bondi, Alessandro;Bianco, Gabriele;Iannaccone, Marco;Costa, Cristina;Cavallo, Rossana
2022-01-01

Abstract

The lack of internationally approved breakpoint and a handy susceptibility testing reduces fosfomycin usefulness against Pseudomonas aeruginosa. Previous works defined low or moderate agreement between commercial methods and the reference method (agar dilution [AD]). In particular, data lack about testing against P. aeruginosa. We compared disk diffusion (DD), E-test (ET), and automated broth microdilution (BMD) to AD by testing 150 P. aeruginosa isolates. We obtained better categorical agreement (CA) for DD and ET for minimal inhibitory concentration >128 mg/L (84.7% and 92.7%, respectively), but with high very major error (VME). BMD had the lowest VME rate (2/42), but with 64% CA and 52/108 major errors. We cannot define a method comparable to AD. Larger studies, as well as the definition of a breakpoint value are needed for fosfomycin against P. aeruginosa.
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1528
Pseudomonas aeruginosa; agar dilution; breakpoint; fosfomycin; susceptibility testing
Peradotto, Marco; Bondi, Alessandro; Bianco, Gabriele; Iannaccone, Marco; Barbui, Anna Maria; Costa, Cristina; Cavallo, Rossana
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2318/1872857
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