Bruins Marjan J, Bloembergen Peter, Ruijs Gijs J H M, Wolfhagen Maurice J H M
Laboratory of Clinical Microbiology and Infectious Diseases, Isala Klinieken, 8021 AM Zwolle, The Netherlands.
J Clin Microbiol. 2004 Jan;42(1):7-11. doi: 10.1128/JCM.42.1.7-11.2004.
Inoculation of an automated system for rapid identification (ID) and antimicrobial susceptibility testing (AST) directly from positive blood culture bottles will reduce the turnaround time of laboratory diagnosis of septicemic patients, which benefits clinical outcome and decreases patient costs. Direct test results, however, must always be confirmed by testing a pure overnight culture, which is the "gold standard." We studied the accuracy of direct testing versus repeat testing in order to investigate the possibility of refraining from repeat testing. We also assessed the clinical risk of reporting results based on direct testing only. We inoculated Vitek 2 (bioMérieux) directly from 410 positive BACTEC 9240 (BD) blood culture bottles containing gram-negative rods and studied the ID and AST results. In a comparison of direct inoculation with the standard method, a total of 344 isolates of Enterobacteriaceae and Pseudomonas aeruginosa were tested, and 93.0% were correctly identified. Of the 39 (10.2%) samples that contained bacilli not identifiable by Vitek 2, only 1 gave a conclusive, correct result. The overall MIC agreement among 312 isolates was 99.2%, with 0.8% very major and 0.02% major error rates. Of only three (polymicrobial) samples, the direct susceptibility pattern would be reported to the clinician as too sensitive. Vitek 2 results obtained from direct inoculation of blood culture bottles containing gram-negative bacilli are safe enough for immediate reporting, provided that ID and AST are consistent. Repeat testing is not necessary, unless Gram stain or overnight subculture results raise doubt about the purity of the culture.
直接从阳性血培养瓶接种自动化系统进行快速鉴定（ID）和抗菌药物敏感性测试（AST），将缩短败血症患者实验室诊断的周转时间，这有利于临床治疗结果并降低患者费用。然而，直接检测结果必须始终通过检测纯过夜培养物来确认，这是“金标准”。我们研究了直接检测与重复检测的准确性，以探讨避免重复检测的可能性。我们还评估了仅基于直接检测报告结果的临床风险。我们直接从410个含有革兰氏阴性杆菌的阳性BACTEC 9240（BD）血培养瓶中接种Vitek 2（bioMérieux），并研究了ID和AST结果。在直接接种与标准方法的比较中，共检测了344株肠杆菌科细菌和铜绿假单胞菌，93.0%被正确鉴定。在39个（10.2%）含有Vitek 2无法鉴定的杆菌的样本中，只有1个给出了决定性的正确结果。312株分离株的总体MIC一致性为99.2%，极重大错误率为0.8%，重大错误率为0.02%。只有三个（多微生物）样本中，直接药敏模式对临床医生来说会报告为过于敏感。从直接接种含有革兰氏阴性杆菌的血培养瓶获得的Vitek 2结果足够安全，可以立即报告，前提是ID和AST一致。除非革兰氏染色或过夜传代培养结果对培养物的纯度产生怀疑，否则无需进行重复检测。
