革兰阴性菌引起的血培养阳性标本的直接鉴定药敏试验

目的 为进一步缩短实验室菌血症诊断时间,评估联合法阳性血培养直接鉴定药敏试验的可行性.方法 将血培养瓶放人BACTEC 9000血培养系统进行培养筛选.选取65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真空分离管离心分离血细胞.在收集到足量菌液后,用Phoenix 100 NMIC/ID-4革兰阴性菌鉴定药敏卡做0.25 McF和0.5 McF直接鉴定药敏试验.用标准方法及哑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 0.25 McF直接鉴定试验,65株中的63株(96.9%)准确鉴定.0.5 MeF直接鉴定试验,65株中的59株(90.8%)准确鉴定.0.25 McF直接药敏试验标准符合率97.8%以上.0.5 McF直接药敏试验标准符合率95.9%以上.KB法血标本直接药敏试验标准符合率96.4%以上,但微小错误率高于联合药敏法.结论 采用0.25 McF、0.5 McF两种菌液浓度法进行血培养阳性标本鉴定药敏试验是切实可行的.联合法0.25 McF菌液浓度的直接鉴定药敏试验具有明显优势,对临床具有很好的及时、有效地指引作用.

Abstract：

Objective To reduce the turnaround time for laboratory diagnosis of bacteremia, the feasibility of rapid identification and susceptibility testing using samples taken directly from positive blood culture bottles was evaluated. Methods The growth of microorganisms in blood culture bottles was screened by the BACTEC 9000 blood culture system. 65 positive blood culture bottles containing gram-negative bacteria were adopted to test. Culture fluid was injected into BD SST vacutainer and centrifuged to pellet blood cells. After collecting required McFarland units, they were cultured on Phoenix 100 NMIC/ID-4(identification-gram-negative bacteria and susceptibility testing) cards using 0.25 McF and 0.5 McF methods respectively. They were also evaluated by the standard method, involving subculture tests from positive blood culture bottles. Results 63 of 65 gram-negative bacteria (96. 9% ) were correctly identified with 0. 25 McF method. 59 of 65 gram-negative bacteria(90.8% ) were correctly identified with 0.5 McF method. For antimicrobial susceptibility testing, the 0.25 McF direct method had an agreement rate more than 94% , the 0.5 McF method was more than 85.7% and direct blood sample KB method was more than 93.8% compared to the standard method. But the overall minor error rate in susceptibility testing of direct blood sample KB method is higher than other methods. Conclusion Applying 0. 25 McF and 0. 5 McF rapid identification and susceptibility test was practical. During to possessing more prominent advantages, laboratory put the 0. 25 McF direct method into practice had a timely, remarkable significance.

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

Objective To reduce the turnaround time for laboratory diagnosis of bacteremia, the feasibility of rapid identification and susceptibility testing using samples taken directly from positive blood culture bottles was evaluated. Methods The growth of microorganisms in blood culture bottles was screened by the BACTEC 9000 blood culture system. 65 positive blood culture bottles containing gram-negative bacteria were adopted to test. Culture fluid was injected into BD SST vacutainer and centrifuged to pellet blood cells. After collecting required McFarland units, they were cultured on Phoenix 100 NMIC/ID-4(identification-gram-negative bacteria and susceptibility testing) cards using 0.25 McF and 0.5 McF methods respectively. They were also evaluated by the standard method, involving subculture tests from positive blood culture bottles. Results 63 of 65 gram-negative bacteria (96. 9% ) were correctly identified with 0. 25 McF method. 59 of 65 gram-negative bacteria(90.8% ) were correctly identified with 0.5 McF method. For antimicrobial susceptibility testing, the 0.25 McF direct method had an agreement rate more than 94% , the 0.5 McF method was more than 85.7% and direct blood sample KB method was more than 93.8% compared to the standard method. But the overall minor error rate in susceptibility testing of direct blood sample KB method is higher than other methods. Conclusion Applying 0. 25 McF and 0. 5 McF rapid identification and susceptibility test was practical. During to possessing more prominent advantages, laboratory put the 0. 25 McF direct method into practice had a timely, remarkable significance.