Comparative evaluation of VITEK® 2 and three commercial gradient strip assays for daptomycin susceptibility testing of Staphylococcus aureus

MRSA remains a major cause of severe nosocomial infections and the increased use of vancomycin and daptomycin for MRSA treatment over the last decade has led to the isolation of MRSA strains with decreased daptomycin susceptibility. In addition, a growing number of MSSA isolates with reduced susceptibility to daptomycin have been described lately. Surveillance of the emergence of such a daptomycin-non-susceptible MSSA population requires prompt and reliable daptomycin susceptibility testing. Therefore, this work aimed to evaluate the ability of commonly used methods to detect daptomycin resistance in clinical microbiological laboratories.