Investigation of linezolid, tigecycline and daptomycin susceptibility in vancomycin-resistant enterococci using E-test method

Objective: Problems are encountered in the therapy of enterococcal infections due to their intrinsic resistance to many antibiotics and increasing glycopeptide resistance in recent years. That is why clinical trials are required to test new antibiotics for the treatment. In this study, we investigated susceptibility to linezolid, daptomycin and tigecycline in vancomycin-resistant enterococci (VRE) strains. Methods: Totally, 58 of VRE strains obtained from various clinical specimens were included in the study. The strains identified as enterococci by conventional methods and Phoenix automated system (Becton Dickinson, USA) was utilized for further identification of the strains and determination of their resistance to vancomycin. Vancomycin resistance in these strains was confirmed by E-test. Using the same method 58 VRE strains were tested for linezolid and daptomycin and 47 VRE strains for tigecycline. Results: MIC50, MIC90 and MIC range for vancomycinresistant strains was detected as 0.75, 1.5, and 0047-2 µg/ml for linezolid; 1, 2 and 0.19-3 µg/ml for daptomycin and 0064, 0125, and 0.016-0.19 µg/ml for tigecycline, respectively. No strain resistant to linezolid, daptomycin; tigecycline was detected. Conclusion: Although linezolid maintains its importance as effective antibiotic for the treatment of infections caused by VRE, recently introduced daptomycin and tigecycline with their low MIC values occur as good treatment options.