Etestw versus broth microdilution for ceftaroline MIC determination with Staphylococcus aureus: Results from PREMIUM, a European multicentre study

Rafael Cantón, David M. Livermore, María Isabel Morosini, Jazmín Díaz-Regañón, Gian Maria Rossolini, Jan Verhaegen, Reinoud Cartuyvels, Geert Claeys, Hans De Beenhouwer, Michel Delmée, Olivier Denis, Youri Glupczynski, Greet Leven, Pierrette Melin, Denis Pierard, Laura Pagani, Fabio Arena, Francesco Luzzaro, Giovanni Pietro Gesu, Roberto SerraAnnamaria D'Argenio, Mario Sarti, Patrizia Pecile, Annarita Mazzariol, Valeria Biscaro, Esther Manso, Maria Rosaria Catania, Cristina Giraldi, Stefania Stefani, Maria Labonia, Richard Aschbacher, Anna Giammanco, Melo Cristino, Luísa Sancho, José Manuel Diogo, Elmano Ramalheira, Helena Ramos, Dolores Pinheiro, María García-Castillo, Jorge Calvo, Antonio Oliver, Concepción Gimeno, Álvaro Pascual, Fe Tubau Quintano, Rosa Bartolomé, Ramón Cisterna, Emilia Cercenado, Paloma Merino, Francesc Marco, Germán Bou, on behalf of the PREMIUM Study Group

Research output: Contribution to journalArticlepeer-review


Objectives: To compare the concordance of ceftaroline MIC values by reference broth microdilution (BMD) and Etest (bioMérieux, France) for MSSA and MRSA isolates obtained from PREMIUM (D372SL00001), a European multicentre study. Methods: Ceftaroline MICs were determined by reference BMD and by Etest for 1242 MSSA and MRSA isolates collected between February and May 2012 from adult patients with community-acquired pneumonia or complicated skin and soft tissue infections; tests were performed across six European laboratories. Selected isolates with ceftaroline resistance in broth (MIC >1 mg/L) were retested in three central laboratories to confirm their behaviour. Results: Overall concordance between BMD and Etest was good, with >97% essential agreement and >95% categorical agreement. Nevertheless, 12 of the 26 MRSA isolates found resistant by BMD scored as susceptible by Etest, with MICs ≤1 mg/L, thus counting as very major errors, whereas only 5 of 380 MRSA isolates found ceftaroline susceptible in BMD were miscategorized as resistant by Etest. Twenty-one of the 26 isolates with MICs of 2 mg/L by BMD were then retested twice by each of three central laboratories: BMD MICs of 2 mg/L were consistently found for 19 of the 21 isolates. Among 147 Etest results for these 21 isolates (original plus six repeats per isolate) 112 were >1 mg/L. Conclusions: BMD and Etest have good overall agreement for ceftaroline against Staphylococcus aureus; nevertheless, reliable Etest-based discrimination of the minority of ceftaroline-resistant (MIC 2 mg/L) MRSA is extremely challenging, requiring careful reading of strips, ideally with duplicate testing.

Original languageEnglish
Pages (from-to)431-436
Number of pages6
JournalJournal of Antimicrobial Chemotherapy
Issue number2
Publication statusPublished - Jan 1 2017

ASJC Scopus subject areas

  • Pharmacology
  • Pharmacology (medical)
  • Infectious Diseases


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