革兰阴性菌引起的血培养阳性标本直接细菌鉴定和药敏的应用

目的 评估血培养阳性标本直接细菌鉴定和药敏可行性.方法 将血培养瓶放入Bact/Alert 3D 60血培养系统进行培养筛选.选取78份含革兰阴性杆菌的阳性血培养瓶进行试验.抽取培养液,用BD真空分离管离心血细胞.在收集到足量菌液后,用VITEK-32革兰阴性菌鉴定药敏卡做直接鉴定药敏试验.用标准方法及亚培养后的鉴定药敏试验对直接鉴定药敏试验进行评估.结果 VITEK-32直接鉴定试验,78株中的74株(94.9％)准确鉴定,直接药敏试验标准符合率95.6％.KB法血标本直接药敏试验标准符合率96.2％,但微小错误率高于VITEK-32直接药敏法.结论 Bact/Alert血培养阳性标本直接VITEK-32细菌鉴定和药敏对革兰阴性菌是切实可行的,可大幅度缩短时间,为临床及时修正用药提供依据,具有较高的应用价值.

Rapid identification and susceptibility testing of positive blood culture caused by gram negative bacteria

Objective To evaluate the feasibility of direct identification and antimicrobial susceptibility tests of positive blood culture samples. Methods The growth of microorganisms in blood culture bottles was screened by the Bact/Alert 3D 60 blood culture system. 78 positive blood culture bottles containing gram-negative bacteria were selected for the test. Culture fluid was injected into BD SST vacutainer and centrifuged to pellet blood cells. After collecting required McFarland units, they were cultured on VITEK-32 GNI ＋/GNS-506 for indenfication of gram-negative bacteria and susceptibity testing. They were also evaluated by the standard method involving subculture tests from positive blood culture bottles. Results 74 of 78 gram-negative bacteria （94.9%） were correctly identified. For antimicrobial susceptibility testing, the direct method had a coincidence rate of 95.6% and the direct blood sample KB methods had 96.2%, compared to the stadard method. But the overall minor error rate in susceptibility testing of direct blood samples KB method was higher than the other methods. Conclusion These finding suggest that VITEK-32 cards inoculated directly from Bact/Alert culture positive bottles can provide acceptable bacterial identi- fication or susceptility testing for gram-negative bacteria, and shorten the time lapse between initial inoculation of blood cuture and the reporting of results.