Phenotypic and Genotypic Analyses of Methicillin-Resistant Staphylococcus aureus Isolates from a Community Hospital

Use of Daptomycin to Treat Infections With Methicillin-Resistant Staphylococcus aureus Isolates Having Vancomycin Minimum Inhibitory Concentrations of 1.5 to 2 µg/mL

“…The in vitro surveillance results indicate that MRSA isolates having vancomycin MICs of 1.5 to 2 µg/mL have remained highly susceptible to daptomycin. [38][39][40][41][42][43][44][45][46][47][48][49] Although not a significant factor in the in vitro studies reviewed (given the high and consistent susceptibility rates), it is important to consider the underlying MIC methodology when comparing the results of multiple studies because of testing method variations. 15 Additionally, it is important to consider that most studies linking higher vancomycin MIC values to poorer therapeutic outcome have used Etest.…”

“…MRSA susceptibility is routinely assessed in large surveillance studies, but only rarely are MRSA subpopulations with vancomycin MICs of 1.5 to 2 µg/mL analyzed for antimicrobial activity. [38][39][40][41][42][43][44][45][46][47][48][49] Presence of these isolates is often indicated in surveillance data by the MIC range, MIC 50 or MIC 90 . [57][58][59] However, without a subgroup analysis, clinicians are unable to understand the activity of daptomycin against MRSA isolates with vancomycin MICs of 1.5 to 2 µg/mL in the region studied.…”

“…2,[60][61][62] In all, 12 surveillance studies were identified, which included a subgroup analysis of MRSA isolates with 1.5 to 2 µg/mL vancomycin MICs. [38][39][40][41][42][43][44][45][46][47][48][49] These included isolates from Canada (n = 28), Europe (n = 128), India (n = 18), Israel (n = 165), Italy (n = 8), Korea (n = 317), Taiwan (n = 81), Spain (n = 33), Turkey (n = 116), the United States (n = 533), and unspecified worldwide (n = 18). [38][39][40][41][42][43][44][45][46][47][48][49] A weighted average from these studies indicated that 99.1% of the isolates were daptomycin susceptible (MIC ≤1 µg/mL).…”

“…This resulted in 12 in vitro and 7 clinical studies. [38][39][40][41][42][43][44][45][46][47][48][49][50][51][52][53][54][55][56]…”