Cantón E, Pemán J, Sastre M, Valentín A, Bosch M, Espinel-Ingroff A
Unidad de Microbiologia Experimental del Centro de Investigacion, Hospital Universitario La Fe, Valencia, Spain.
Rev Esp Quimioter. 2006 Sep;19(3):267-74.
Standardized broth dilution methods are cumbersome for routine use in a clinical laboratory to study antifungal yeast susceptibility. Recently, the CLSI has standardized a disk diffusion method faster and more suitable to study fluconazole and voriconazole susceptibility. The objectives of the present study were to determine: a) the suitability of the Neo-Sensitabs tablets to study fluconazole susceptibility; b) whether Mueller-Hinton agar with methylene blue (MHAG-AM) could be used in the E-test method; and c) the interaction of the methylene blue with RPMI medium. A total of 84 blood stream yeast isolates were used (25 C. albicans, 7 C. parapsilosis, 10 C. tropicalis, 12 C. glabrata, 7 C. krusei, 4 C. lusitaniae and 19 C. neoformans). The methylene blue makes sharper inhibition zones both in MHAG-AM and RPMI media. With fluconazole Neo-Sensitabs tablets, the lowest percentage of very major errors was found in MHAG-AM and the greatest in RPMIG. In both diffusion methods and culture media, the very major errors were found in C. albicans, C. tropicalis (only with Neo-Sensitabs) and C. glabrata. The percentage of fluconazole-resistant strains was lower in the media that contained glucose (2%). Neo-Sensitabs tablets are a reliable alternative to the dilution methods to detect fluconazole susceptibility. In the case of resistance, more studies are required; nevertheless, inhibition zone > or =17 mm should be applied to define fluconazole resistance.
标准化肉汤稀释法在临床实验室用于研究抗真菌酵母药敏时操作繁琐。最近，临床和实验室标准协会（CLSI）已将一种纸片扩散法标准化，该方法更快且更适合研究氟康唑和伏立康唑的药敏情况。本研究的目的是确定：a）Neo - Sensitabs片剂用于研究氟康唑药敏的适用性；b）含亚甲蓝的穆勒 - 欣顿琼脂（MHAG - AM）是否可用于E试验法；c）亚甲蓝与RPMI培养基的相互作用。共使用了84株血流酵母分离株（25株白色念珠菌、7株近平滑念珠菌、10株热带念珠菌、12株光滑念珠菌、7株克柔念珠菌、4株葡萄牙念珠菌和19株新生隐球菌）。亚甲蓝在MHAG - AM和RPMI培养基中均能形成更清晰的抑菌圈。使用氟康唑Neo - Sensitabs片剂时，在MHAG - AM中发现的极重大错误百分比最低，在RPMI - G中最高。在两种扩散法和两种培养基中，极重大错误均见于白色念珠菌、热带念珠菌（仅使用Neo - Sensitabs片剂时）和光滑念珠菌。在含2%葡萄糖的培养基中，氟康唑耐药菌株的百分比更低。Neo - Sensitabs片剂是检测氟康唑药敏的稀释法的可靠替代方法。对于耐药情况，还需要更多研究；不过，应采用抑菌圈≥17 mm来定义氟康唑耐药。
