Background: Fosfomycin (FOS) is an older antimicrobial agent newly rediscovered as a possible treatment for infections with limited therapeutic options (e.g., Gram-negative bacteria with difficult-to-treat resistance, DTR), especially in intravenous form. However, for correct usage of FOS, it is necessary to have a reliable susceptibility testing method suitable for routine practice and robust interpretation criteria. Results: The results were interpreted according to 2023 interpretation criteria provided by the European Committee on Antimicrobial Susceptibility Testing (EUCAST). DTR Gram-negatives were more likely to be resistant to FOS (45% in Enterobacterales and 20% in P. aeruginosa) than non-DTR (10% and 6.7%, resp.). All isolates of S. aureus were susceptible to FOS. In Gram-negatives, all agreement values were unacceptable. Etest® performed better in the DTR cohort (categorical agreement, CA, 80%) than in the non-DTR cohort (CA 45.7%). There were no very major errors (VREs) observed in P. aeruginosa. S. aureus had surprisingly low essential agreement (EA) rates (53% for MRSA and 47% for MSSA) for Etest®, but categorical agreement was 100%. Methods: A total of 130 bacterial isolates were tested and compared using the disc diffusion method (DD) and gradient strip method (Etest®) with the reference method (agar dilution, AD). The spectrum of isolates tested was as follows: 40 Enterobacterales (20 DTR vs. 20 non-DTR), 30 Pseudomonas aeruginosa (15 DTR vs. 15 non-DTR), and 60 Staphylococcus aureus (30 methicillin-susceptible, MSSA, vs. 30 methicillin-resistant, MRSA). Conclusions: Neither one of the tested methods was identified as a suitable alternative to AD. It would be beneficial to define more interpretation criteria, at least in some instances.
- Publication type
- Journal Article MeSH
- MeSH
- Anti-Bacterial Agents administration & dosage therapeutic use MeSH
- Borrelia burgdorferi Group MeSH
- Immunoassay MeSH
- Humans MeSH
- Lyme Disease * diagnosis epidemiology drug therapy MeSH
- Lyme Neuroborreliosis diagnosis drug therapy MeSH
- Polymerase Chain Reaction MeSH
- Check Tag
- Humans MeSH
- Publication type
- Review MeSH
- MeSH
- Travel MeSH
- Humans MeSH
- Immunization Programs MeSH
- Immunization Schedule MeSH
- Spleen immunology pathology MeSH
- Pregnancy drug effects MeSH
- Vaccination * methods MeSH
- Vaccines classification therapeutic use MeSH
- Check Tag
- Humans MeSH
- Pregnancy drug effects MeSH
- Publication type
- Review MeSH
- MeSH
- Anti-Bacterial Agents classification therapeutic use MeSH
- Drug Resistance, Microbial * drug effects MeSH
- Gram-Negative Bacteria enzymology MeSH
- Cross Infection * MeSH
- beta-Lactamase Inhibitors therapeutic use MeSH
- Carbapenems therapeutic use MeSH
- Humans MeSH
- Microbial Sensitivity Tests MeSH
- Communicable Diseases, Emerging MeSH
- Drug Synergism MeSH
- Check Tag
- Humans MeSH
- MeSH
- Anti-Bacterial Agents administration & dosage MeSH
- Crutches adverse effects MeSH
- Denervation MeSH
- Middle Aged MeSH
- Humans MeSH
- Lyme Disease * diagnosis epidemiology drug therapy classification complications MeSH
- Minocycline adverse effects therapeutic use MeSH
- Mononeuropathies diagnosis complications MeSH
- Median Nerve pathology MeSH
- Peripheral Nervous System pathology MeSH
- Disease Progression MeSH
- Vasculitis chemically induced drug therapy MeSH
- Check Tag
- Middle Aged MeSH
- Humans MeSH
- Male MeSH
- Publication type
- Case Reports MeSH
- Review MeSH
