Dipartimento di Scienze di Sanità Pubblica, 'Sapienza' University of Rome, Rome, Italy.
Dipartimento di Scienze Biomediche, 'Campus Bio-Medico' University, Rome, Italy.
J Med Microbiol. 2010 Jun;59(Pt 6):672-678. doi: 10.1099/jmm.0.016444-0. Epub 2010 Feb 25.
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.
采用 Vitek 2 系统、Phoenix 系统、Etest 法、肉汤微量稀释法和纸片扩散法检测 30 株粪肠球菌临床分离株对替考拉宁、万古霉素和利奈唑胺的敏感性。采用 PCR 和 PCR-RFLP 法分别检测 vanA 和 vanB 耐药基因及 23S rRNA 基因 G2576T 突变。Vitek 2 系统检测替考拉宁的耐药率为 3%，Phoenix 系统检测的耐药率为 57.6%；Vitek 2 系统检测万古霉素的耐药率为 56.7%，Phoenix 系统检测的耐药率为 86.7%。25 株携带 vanA 基因的菌株中，仅有 2 株被明确鉴定为 VanA 表型。唯一一株携带 G2576T 突变的菌株不携带 vanA 基因，且纸片扩散法、Vitek 2 系统和肉汤微量稀释法（MIC>8μg/ml）检测对利奈唑胺耐药，但Phoenix 系统和 Etest 法（MIC<或=4μg/ml）检测对利奈唑胺敏感。因此，本研究中采用的药敏试验方法不能明确检测到对糖肽类和利奈唑胺的耐药性。
