两种MALDI-TOF MS系统快速鉴定血培养中白念珠菌以外酵母样真菌

Rapid identification of Yeast like fungi outside of Candida albicans isolated form blood culture by two MALDI-TOF MS systems

目的评价2种基质辅助激光解析电离飞行时间质谱(MALDI-TOF MS)系统(Autoflex MALDI-TOF MS和Vitek MALDI-TOF MS)在快速鉴定血培养中分离的白念珠菌以外酵母样真菌的应用。方法收集复旦大学附属中山医院2010年10月至2013年1月住院患者血培养中分离的白念珠菌以外酵母样真菌59株,以真菌内转录间隔区(ITS)测序鉴定结果为金标准,比较Autoflex MALDI-TOF MS、Vitek MALDI-TOF MS和API 20C AUX 3种系统鉴定的准确性。结果 59株菌株包含了11种真菌,其中近平滑复合体30株(占50.8%)、热带念珠菌11株(占18.6%)、光滑念珠菌8株(占13.6%)、克柔念珠菌2株(占3.4%)、新生隐球菌2株(占3.4%)、异常威克汉姆酵母2株(占3.4%)、季也蒙念珠菌复合体1株(占1.7%)、葡萄牙念珠菌1株(占1.7%)、阿萨希毛孢子菌1株(占1.7%)和酿酒酵母1株(占1.7%)。3种系统鉴定真菌总的准确性分别为Autoflex MALDITOF MS 93.2%、Vitek MALDI-TOF MS 83.1%和API 20C AUX 79.7%,2种MALDI-TOF MS比较,差异无统计学意义(P=0.155)。其中对白念珠菌以外酵母样真菌的鉴定准确性分别为Autoflex MALDI-TOF MS 100.0%、Vitek MALDI-TOF MS 84.9%和API 20C AUX 84.9%,2种MALDI-TOF MS比较,差异具有统计学意义(P=0.006)。对念珠菌属外的少见真菌鉴定准确性分别为Autoflex MALDI-TOF MS 33.3%、Vitek MALDI-TOF MS66.6%和API 20C AUX 33.3%。结论 MALDI-TOF MS系统和目前常规生化鉴定方法相比,具有快速、操作简便、结果准确等优点;对于临床血培养分离真菌的鉴定,Autoflex MALDI-TOF MS鉴定准确性和Vitek MALDI-TOF MS相似,但对常见非白念珠菌的鉴定,Autoflex MALDI-TOF MS鉴定准确性优于Vitek MALDI-TOF MS。

Objective To evaluate the application of 2 matrix-assisted laser desorption / ionization-time of flight mass spectrometry（ MALDI-TOF MS）,Autoflex MALDI-TOF MS and Vitek MALDI-TOF MS,for the identification of Yeast like fungi outside of Candida albicans isolated from blood culture. Methods A total of 59 isolates were collected from blood culture from October 2010 to February 2013 among inpatients in Zhongshan Hospital,Fudan University. The results of fungus internal transcribed spacer（ ITS） sequencing were as golden standards. The correct identification rates of Autoflex MALDI-TOF MS,Vitek MALDI-TOF MS and API 20 C AUX were analyzed comparatively. Results The 59 isolates included 11 types of fungi,namely,Candida parapsilosis complex（ 30 isolates,50. 8%）,Candida tropicalis（ 11 isolates,18. 6%）,Candida glabrata（ 8 isolates,13. 6%）,Candida krusei（ 2 isolates,3. 4%）,Wickerhamomy cesanomalus（ 2 isolates,3. 4%）,Cryptococcus neoformans（ 2 isolates,3. 4%）,Candida iusitaniae（ 1 isolate,1. 7%）,Candida guilliermondii（ 1 isolate,1. 7%）,Trichosporon asahii（ 1 isolate,1. 7%） and Saccharomyces cerevisiae（ 1isolate,1. 7%）. The correct identification rates by Autoflex MALDI-TOF MS,Vitek MALDI-TOF MS and API 20 C AUX were 93. 2%,83. 1% and 79. 7%,respectively,and there was no statistical significance between the 2 MALDITOF MS systems（ P = 0. 155）. The correct identification rates for yeast like fungi outside of Candida albicans by Autoflex MALDI-TOF MS, Vitek MALDI-TOF MS and API 20 C AUX were 100. 0%,84. 9% and 84. 9%,respectively,and there was statistical significance between the 2 MALDI-TOF MS systems（ P = 0. 006）. The correct identification rates of rarely clinical encountered fungi by Autoflex MALDI-TOF MS,Vitek MALDI-TOF MS and API20 C AUX were 33. 3%,66. 6% and 33. 3%,respectively. Conclusions MALDI-TOF MS system is rapid,simple and accurate compared with current routine biochemical identification methods. The performance of Autoflex MALDITOF MS is similar with that of Vitek MALDI-TOF MS for the identification of isolated fungi from blood culture. The performance of Autoflex MALDI-TOF MS is better than that of Vitek MALDI-TOF MS for the identification of yeast like fungi outside of Candida albicans.