Department of Medical Microbiology, Care And Public Health Research Institute, Maastricht University Medical Center, PO Box 5800, 6202AZ Maastricht, the Netherlands.
BMC Microbiol. 2011 Jun 30;11:156. doi: 10.1186/1471-2180-11-156.
Rapid identification (ID) and antibiotic susceptibility testing (AST) of the causative micro-organism of bloodstream infections result in earlier targeting of antibiotic therapy.In order to obtain results of ID and AST up to 24 hours earlier, we evaluated the accuracy of direct inoculation of the Phoenix system from positive blood cultures (BACTEC) by using Serum Separator Tubes to harvest bacteria from positive blood cultures. Results were compared to those of standard Phoenix procedure. Discrepancies between the two methods were resolved by using the API system, E-test or microbroth dilution.
ID with the direct method was correct for 95.2% of all tested Enterobacteriaceae (n = 42) and 71.4% of Pseudomonas aeruginosa strains (n = 7).AST with the direct method showed a categorical agreement for Gram-negative rods (GNR) of 99.0%, with 0.7% minor errors, 0.3% very major errors and no major errors. All antibiotics showed an agreement of >95%.The direct method for AST of Staphylococcus (n = 81) and Enterococcus (n = 3) species showed a categorical agreement of 95.4%, with a minor error rate of 1.1%, a major error rate of 3.1% and a very major error rate of 0.4%. All antibiotics showed an agreement of >90%, except for trimethoprim-sulfamethoxazole and erythromycin.
Inoculation of Phoenix panels directly from positive blood cultures can be used to report reliable results of AST of GNR a day earlier, as well as ID-results of Enterobacteriaceae. For Staphylococcus and Enterococcus species, results of AST can also be reported a day earlier for all antibiotics, except for erythromycin and trimethoprim-sulfamethoxazole.
快速鉴定（ID）和抗生素敏感性测试（AST）血流感染的病原体可使抗生素治疗更早地针对目标。为了在 24 小时内更早获得 ID 和 AST 结果，我们评估了使用血清分离管从阳性血培养物（BACTEC）直接接种凤凰系统以从阳性血培养物中收获细菌的准确性。结果与标准凤凰程序进行了比较。通过使用 API 系统、E 试验或微量肉汤稀释法解决了两种方法之间的差异。
直接法鉴定的 ID 对所有测试的肠杆菌科（n = 42）的 95.2%和铜绿假单胞菌株（n = 7）的 71.4%均正确。直接法 AST 对革兰氏阴性杆菌（GNR）的分类一致性为 99.0%，微小误差率为 0.7%，重大误差率为 0.3%，无重大误差。所有抗生素的一致性均>95%。直接法用于鉴定金黄色葡萄球菌（n = 81）和肠球菌（n = 3）的 AST 的分类一致性为 95.4%，微小误差率为 1.1%，重大误差率为 3.1%，非常重大误差率为 0.4%。除了甲氧苄啶-磺胺甲恶唑和红霉素外，所有抗生素的一致性均>90%。
从阳性血培养物中直接接种凤凰面板可用于提前一天报告 GNR 的 AST 和肠杆菌科的可靠 ID 结果。对于金黄色葡萄球菌和肠球菌，除了红霉素和甲氧苄啶-磺胺甲恶唑外，所有抗生素的 AST 结果也可提前一天报告。
