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Antimicrobial susceptibility of daptomycin and comparator agents tested against bloodstream isolates of Staphylococcus aureus: analysis of a 5year trend in European medical centres (20052009)

Abstract number: P1671

Biedenbach D., Jones R., Sader H.

Objectives: To evaluate daptomycin activity against S. aureus collected from patients with bloodstream infections (BSI) in European (EU) hospitals. Daptomycin is a natural lipopeptide derived from Streptomyces roseosporus that is rapidly bactericidal against Gram-positive pathogens. Daptomycin is approved by the European Medicine Agency (EMEA) for treating complicated skin and skin structure infections and S. aureus-associated bacteremia and right-sided endocarditis, including those caused by methicillin-resistant S. aureus (MRSA).

Methods:S. aureus BSI isolates (4,886) were consecutively collected from 29 sites in 13 EU countries. Susceptibility (S) was determined by the CLSI broth microdilution method. Cation-adjusted Mueller-Hinton broth was used for testing all agents and was supplemented to 50 mg/L of calcium for testing daptomycin as recommended by the CLSI and EUCAST.

Results: Between 2005 and 2009, the MRSA rate declined nearly 9% in EU, with an overall rate of 27.4% during the five year period. The lowest MRSA rate was observed in Sweden (two sites, 1.1%) and the highest rate was in Greece (two sites, 53.8%). Resistance (R) to erythromycin and clindamycin also declined from 33.6 and 18.1% in 2005 to 26.4 and 10.1% in 2009, respectively. The highest MIC value for daptomycin was 1 mg/L (100.0% S using CLSI and EUCAST breakpoints) with MIC50 and MIC90 values of 0.25 and 0.5 mg/L, respectively. Vancomycin (MIC50/90, 1/1 mg/L; 100.0% S) and linezolid (MIC50/90, 1/2 mg/L; >99.9% S) were two- to four-fold less active than daptomycin. Only one linezolid-R was observed and quinupristin/dalfopristin-R isolates were only observed in France. Daptomycin potency was very uniform among the countries evaluated and daptomycin MIC distributions did not vary significantly overtime (Table).

Conclusions: Daptomycin showed consistent potency against an extensive collection of clinical isolates of S. aureus, including MRSA, from numerous EU medical centres over the last five years. All isolates were S to daptomycin, which was more potent compared to vancomycin and linezolid and has excellent activity against S. aureus isolates with co-R to other antimicrobial classes.

YearOrganism (no.)Cumulative % inhibited at daptomycin MIC (mg/L) of:
  leqslant R: less-than-or-eq, slant0.060.120.250.51
2005MSSA (701)0.03.780.099.7100.0
 MRSA (323)0.01.959.199.1100.0
2006MSSA (826)0.07.192.399.8100.0
 MRSA (284)0.42.873.699.7100.0
2007MSSA (823)0.05.089.399.8100.0
 MRSA (321)0.33.777.998.8100.0
2008MSSA (814)0.12.766.799.6100.0
 MRSA (298)0.02.748.398.3100.0
2009MSSA (384)0.01.058.3100.0
 MRSA (112)0.02.750.097.3100.0

Session Details

Date: 10/04/2010
Time: 00:00-00:00
Session name: Abstracts 20th European Congress of Clinical Microbiology and Infectious Diseases
Subject:
Location: Vienna, Austria, 10 - 13 April 2010
Presentation type:
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