Daptomycin susceptibility testing of linezolid-resistant Staphylococcus cohnii isolates
Abstract number: P543
Papaioannou V., Tsiplakou S., Stylianakis A., Paraskevopoulou D., Zoumpouloglou F., Lykou D., Koutsoukou A.
Objectives: Daptomycin is a cyclic lipopeptide with potent activity and broad spectrum against Gram-positive bacteria approved for the treatment of complicated skin and skin structure infections and bacteraemia, including right sided endocarditis. The aim of this study was to evaluate the susceptibility of daptomycin against 26 clinical isolates of multi-drug resistant Staphylococcus cohnii, all being resistant to linezolid, recovered from blood cultures.
Methods: 26 non-duplicate isolates of Staphylococcus cohnii were tested for susceptibility to daptomycin with the method of E-test (AB Biodisk, Solna, Sweden) according to the manufacturer's recommendations. Those isolates were isolated from blood cultures of patients hospitalised in KAT hospital during a period of approximately three years (July 2005 to November 2007). Susceptibility testing was performed using the VITEK 2 System (Biomerieux, France). MICs for linezolid were also determined with the use of E-test. Interpretation of MICs was according to CLSI guidelines.
Results: All isolates were found resistant to oxacillin, ciprofloxacin, clindamycin, erythromycin, quinupristin/dalfopristin and susceptible to gentamicin, teicoplanin, tetracyclin, trimethoprim/sulfamethoxazole, and vancomycin. Susceptibility to fucidic acid and rifampicin varied from intermediate to resistant. Most isolates were intermediately resistant to moxifloxacin except for two that were resistant. All isolates were resistant to linezolid (MIC 8 mg/L) and susceptible to daptomycin with MICs ranging between 0.5 mg/L (8 isolates, 30.8%), to 0.75 mg/L (11 isolates, 42.3%) and up to 1.0 mg/L (7 isolates, 26.9%).
Conclusion: Daptomycin showed excellent in vitro activity against multi-drug resistant isolates of Staphylococcus cohnii. It seems to be a promising solution to such isolates of Gram-positive bacteria while other therapeutic options such as linezolid, teicoplanin and quinupristin/ dalfopristin are being eliminated by increasing resistance.
|Session name:||18th European Congress of Clinical Microbiology and Infectious Diseases|
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