VITEK-MS质谱仪直接检测BacT/ALERT 3D仪阳性血培养瓶微生物的实验研究

VITEK-MS direct identification of bacteria from positive Bac T/ALERT 3D blood culture bottles

目的评估基质辅助激光解析电离飞行时间质谱(VITEK-MS)仪直接检测Bac T/ALERT 3D仪阳性培养瓶微生物方法的可行性与准确性。方法选取2016年9月-2016年11月安徽医科大学第一附属医院微生物室Bac T/ALERT 3D全自动培养仪当天报告阳性的血培养瓶,差速离心法处理后直接用VITEK-MS进行检测,并与常规鉴定法进行比较。结果 150例阳性培养瓶中,除13例培养瓶中无细菌生长外,VITEK-MS直接鉴定法正确检测出97例(70.8%)菌株,错误检测出10例(7.3%)菌株,30例(21.9%)鉴定无结果。其中,革兰阴性杆菌正确鉴定出61例(88.4%)菌株,鉴定无结果 8例(11.6%);革兰阳性球菌正确鉴定出36例(52.9%)菌株,鉴定错误10例(14.7%),鉴定无结果 22例(32.4%)。结论利用VITEK-MS直接鉴定阳性血培养瓶的方法准确性高、特异性强,革兰阴性杆菌鉴定准确率远高于革兰阳性球菌,且鉴定时间短(只需2 h)。该方法可以作为快速诊断阳性血培养瓶的新方法。

Objective To evaluate the performance of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry system（VITEK-MS） for direct detection of bacteria in the positive bottles by Bac T/ALERT 3 D blood culture system and its identification rate. Methods All positive blood culture botlles reported by Bac T/ALERT 3 D blood culture system that had been obtained from the patients in the First Affiliated Hospital of Anhui Medical University from September to November 2016 were selected. The bacteria were directly detected by VITEK-MS after differential centrifugation, and compared with the results by traditional biochemical identification. Results Among 150 positive blood culture bottles, there was no bacteria growth in 13 bottles; in the rest 137 bottles, VITEK-MS correctly identified 97（70.8%）, wrongly detected 10（7.3%）, and could not identify 30（21.9%）. For Gram-negative bacilli, the correct identification rate was88.4%（61 cases） and 8 cases（11.6%） were not identified. In Gram-positive cocci, the correct and wrong identification rate were 52.9%（36 cases） and 14.7%（10 cases）, and 22 cases（32.4%） could not be identified. Conclusions The method of using VITEK-MS to identify the positive blood culture bottles is accurate and specific. The accurate identification rate of Gram-negative bacilli is much higher than that of Gram-positive cocci. The time for identification is reduced to 2 h. Thus, this method can provide rapid and reliable identification of microorganisms in blood culture bottles.