E-test试条对异质性耐万古霉素葡萄球菌的检测

目的 探讨E—test对异质性耐万古霉素葡萄球菌的检测价值。方法 从连续接触万古霉素的脑心浸液琼脂(BHIA)平板上挑取万古霉素异质性耐药葡萄球菌苗株，应用万古霉素E—test试条、药敏纸片和琼脂平板对倍稀释法测定药敏结果。结果 E—test检测的对万古霉素异质性耐药葡萄球菌MRSHl09，MRSH2，MRSH13，MRSH31，MRSH60，MRSHl08，MRSH73，MRSH97，MRSH102的MIC依次为：16、24、48、48、16、32、24、24mg/L，其中耐药7株占77．8％(7/9)，中介2株占22．2％(2/9)；琼脂对倍稀释法的MIC为：16、32、64、32、16、32、32、16、32mg/L，耐药6株占66．7％(6/9)，中介3株占33．3％(3/9）；药敏纸片直径依次为：14、12、10、11、10、15、13、10，13mm，敏感率为11．1％(1/9)。结论 E—test可以便捷直观地鉴定对万古霉素异质性耐药葡萄球菌的药敏结果，与琼脂平板对倍稀释法接近，优于纸片法。

Significance of E-test strip in identification of heterogeneously vancomycin-resistant Staphylococci spp.

Objective To evaluate the value of E-test strip in the identification of heterogeneously vancomycin-resistant Staphylococci spp. Methods the heterogeneously vancomycin-resistant strains were selected from the Brain Heart Infusion agar plate with continuous exposure to vancomycin. E-test strip, disk diffusion and agar dilution method were used to detect the susceptibility of these bacteria. Results E-test showed that the MIC of heterogeneously vancomycin-resistant Staphylococci MRSH109, MRSH2, MRSH13, MRSH31, MRSH60, MRSH108, MRSA73, MRSH97, MRSA102 were 16, 24, 48, 48, 16, 32, 32, 24, 24mg/L, respectively , in which 77.8% (7/9) of strains were resistant and 22.2% (2/9) intermediate. The agar dilution method showed that the MIC of these bacteria were 16, 32, 64, 32, 16, 16, 32, 32, 32mg/L, respectively of these bacteria, 66.7% (6/9) of strains were resistant and 33.3% (3/9) intermediate. The zone diameter were 14, 12, 10, 11, 10, 15, 13, 10, 13mm, respectively, in which 11.1% (1/9) of strains were sensitive. Conclusion E-test can conveniently identify the heterogeneously vancomycin resistant Staphylococci similar to the agar dilution method and superior to the paper disks.