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Antimicrobial activity of ceftaroline tested against Staphylococcus aureus from the United States and Europe, 20082009

Abstract number: P930

Objectives: To evaluate the potency and spectrum of ceftaroline against contemporary S. aureus strains and the correlation between SCCmec type and ceftaroline MICs. Ceftaroline is a novel, parenteral cephalosporin in late-stage clinical development for treatment of community-acquired pneumonia and complicated skin and skin structure infections. Ceftaroline exhibits broad-spectrum activity against Gram-negative and -positive organisms, including methicillin-resistant S. aureus (MRSA) and multidrug-resistant S. pneumoniae.

Methods: A total of 8742 unique clinical S. aureus strains were consecutively collected in 2008–2009 from 29 hospitals located in Europe (EU; 3899 strains) and 27 in the USA (4843 strains). Strains were tested for susceptibility (S) to ceftaroline and numerous comparators by CLSI broth microdilution methods. Additionally, 100 strains for which SCCmec types had been previously characterized by PCR were tested for S to ceftaroline and selected b-lactams.

Results: MRSA rates were 55.2% in the USA and 25.8% in EU, ranging from 0.8% in Sweden to 59.5% in Greece. Ceftaroline (MIC50, 0.25 mg/L) was 16-fold more active than ceftriaxone (MIC50, 4 mg/L) against methicillin-S S. aureus (MSSA) and showed potent activity against MRSA (MIC50 1 mg/L and MIC90, 1–2 mg/L; see Table). All MRSA were inhibited at leqslant R: less-than-or-eq, slant2 mg/L of ceftaroline except 4 clonally related strains from a Greek hospital and one strain from Italy (MIC 4 mg/L for all). In EU and the USA, 37.1% and 34.6% of MRSA strains were resistant (R) to clindamycin, and 85.9% and 65.9% were R to levofloxacin, respectively. In contrast, trimethoprim/sulfamethoxazole (98.4–98.6% S), linezolid (100.0% S), and vancomycin (100.0% S) remained very active against MRSA. Ceftaroline MIC values were lowest among MRSA strains with SCCmec type IV, followed by those with SCCmec types II, III, and I.

Conclusions: Ceftaroline was very active against a large collection of MSSA and MRSA strains recently (2008–2009) isolated in EU and USA hospitals. Based on its favourable antimicrobial profile, ceftaroline is a very promising anti-staphylococcal therapeutic option widely applicable to EU and the USA. MRSA isolates with SCCmec type IV, which are found in USA pandemic clone USA300 and several clones circulating in EU, exhibited the lowest ceftaroline MIC results.

Organism (no. of strains)Cumulative % inhibited at ceftaroline MIC (mg/L) of:
 leqslant R: less-than-or-eq, slant0.060.120.250.5124
MSSA       
  Europe (2895)0.95.988.399.9100.0--
  USA (2169)0.74.588.499.9100.0--
MRSA       
  Europe (1004)0.00.02.231.683.999.5100.0a
  USA (2674)0.00.11.134.394.7100.0-
aOnly 5 strains (Greece and Italy).

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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