The susceptibility to teicoplanin, vancomycin and linezolid of 30 clinical isolates of Enterococcus faecium was tested by Vitek 2, Phoenix, Etest, broth microdilution and disc diffusion tests. The vanA and vanB resistance genes and the 23S rRNA gene G2576T mutation were detected by PCR and PCR-RFLP, respectively. Resistance rates to teicoplanin ranged from 3% for Vitek 2 to 57.6% for the Phoenix test, and those to vancomycin ranged from 56.7% for Vitek 2 to 86.7% for the Phoenix test. Only two out of 25 strains carrying the vanA gene were univocally recognized as the VanA phenotype. The only strain with the G2576T mutation did not carry the vanA gene and showed resistance to linezolid by the disc diffusion, Vitek 2 and broth dilution methods (MIC>8 microg ml(-1)), but was susceptible when tested with the Phoenix test and Etest (MIC<or=4 microg ml(-1)). Therefore, the resistance to glycopeptides and linezolid was not univocally detected by the susceptibility testing methods used in this study.

Analysis of methods commonly used for glycopeptide and oxazolidinone susceptibility testing in Enterococcus faecium isolates / Raponi, Giammarco; Ghezzi, Maria Cristina; G., Gherardi; Lorino, Giulia; G., Dicuonzo. - In: JOURNAL OF MEDICAL MICROBIOLOGY. - ISSN 0022-2615. - 59:6(2010), pp. 672-678. [10.1099/jmm.0.016444-0]

Analysis of methods commonly used for glycopeptide and oxazolidinone susceptibility testing in Enterococcus faecium isolates

RAPONI, Giammarco;GHEZZI, Maria Cristina;LORINO, Giulia;
2010

Abstract

The susceptibility to teicoplanin, vancomycin and linezolid of 30 clinical isolates of Enterococcus faecium was tested by Vitek 2, Phoenix, Etest, broth microdilution and disc diffusion tests. The vanA and vanB resistance genes and the 23S rRNA gene G2576T mutation were detected by PCR and PCR-RFLP, respectively. Resistance rates to teicoplanin ranged from 3% for Vitek 2 to 57.6% for the Phoenix test, and those to vancomycin ranged from 56.7% for Vitek 2 to 86.7% for the Phoenix test. Only two out of 25 strains carrying the vanA gene were univocally recognized as the VanA phenotype. The only strain with the G2576T mutation did not carry the vanA gene and showed resistance to linezolid by the disc diffusion, Vitek 2 and broth dilution methods (MIC>8 microg ml(-1)), but was susceptible when tested with the Phoenix test and Etest (MIC
2010
01 Pubblicazione su rivista::01a Articolo in rivista
Analysis of methods commonly used for glycopeptide and oxazolidinone susceptibility testing in Enterococcus faecium isolates / Raponi, Giammarco; Ghezzi, Maria Cristina; G., Gherardi; Lorino, Giulia; G., Dicuonzo. - In: JOURNAL OF MEDICAL MICROBIOLOGY. - ISSN 0022-2615. - 59:6(2010), pp. 672-678. [10.1099/jmm.0.016444-0]
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11573/229764
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