In vitro Activity of Dalbavancin against Staphylococci Isolated in Istanbul, Turkey

BACKGROUND: Staphylococci are a major cause of both community- and hospital-acquired infections. Dalbavancin is a new bactericidal second-generation lipoglycopeptide antibiotic to use in the treatment of multidrug-resistant staphylococcal infections. It is important to determine its activity against staphylococci isolated in Turkey. Dalbavancin has not yet been used in antimicrobial therapy in our country. METHOD: Dalbavancin was tested against a total of 453 staphylococcal strains by using the reference broth microdilution method. Organisms tested included: methicillin-resistant Staphylococcus aureus (MRSA; 237 strains), methicillin-susceptible S. aureus (MSSA; 144 strains) and methicillin- resistant coagulase-negative staphylococci (MR-CoNS; 72 strains). RESULTS: MIC(50) and MIC(90) values of dalbavancin against MRSA, MSSA and MR-CoNS were found as ≤0.008 and 0.25 mg/l; 0.016 and 0.125 mg/l; and 0.016 and 0.5 mg/l, respectively. The overall distribution of dalbavancin MIC values ranged from ≤0.008 to 2 mg/l. If the interpretive breakpoint MIC value is ≤1 mg/l, the susceptibility rates of MRSA, MSSA and MR-CoNS strains were determined as 99.6, 100 and 98.6%, respectively. CONCLUSION: The MIC results for dalbavancin have demonstrated a good activity against both methicillin-sensitive and -resistant staphylococci isolated from hospitalized patients.