Infectious Diseases Service, University Hospital Centre and University of Lausanne, Lausanne, Switzerland.
Clin Microbiol Infect. 2014 Apr;20(4):355-60. doi: 10.1111/1469-0691.12329. Epub 2013 Aug 28.
Effective empirical treatment is of paramount importance to improve the outcome of patients with Staphylococcus aureus bacteraemia. We aimed to evaluate a PCR-based rapid diagnosis of methicillin resistance (GeneXpert MRSA) after early detection of S. aureus bacteraemia using matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS). Patients with a first episode of S. aureus bacteraemia identified using MALDI-TOF MS were randomized in a prospective interventional open study between October 2010 and August 2012. In the control group, antibiotic susceptibility testing was performed after MALDI-TOF MS identification on blood culture pellets. In the intervention group, a GeneXpert MRSA was performed after S. aureus identification. The primary outcome was the performance of GeneXpert MRSA directly on blood cultures. We then assessed the impact of early diagnosis of methicillin resistance on the empirical treatment. In all, 197 episodes of S. aureus bacteraemia were included in the study, of which 106 were included in the intervention group. Median time from MALDI-TOF MS identification to GeneXpert MRSA result was 97 min (range 25-250). Detection of methicillin resistance using GeneXpert MRSA had a sensitivity of 99% and a specificity of 100%. There was less unnecessary coverage of MRSA in the intervention group (17.1% versus 29.2%, p 0.09). GeneXpert MRSA was highly reliable in diagnosing methicillin resistance when performed directly on positive blood cultures. This could help to avoid unnecessary prescriptions of anti-MRSA agents and promote the introduction of earlier adequate coverage in unsuspected cases.
对金黄色葡萄球菌菌血症患者进行有效的经验性治疗对于改善患者的预后至关重要。我们旨在评估在使用基质辅助激光解吸电离飞行时间质谱（MALDI-TOF MS）早期检测金黄色葡萄球菌菌血症后，基于 PCR 的快速检测耐甲氧西林金黄色葡萄球菌（GeneXpert MRSA）的效果。使用 MALDI-TOF MS 鉴定的首次金黄色葡萄球菌菌血症患者于 2010 年 10 月至 2012 年 8 月期间进行了一项前瞻性干预性开放研究的随机分组。在对照组中，在 MALDI-TOF MS 鉴定血培养物后进行抗生素药敏试验。在干预组中，在鉴定金黄色葡萄球菌后进行 GeneXpert MRSA。主要结局是 GeneXpert MRSA 直接在血培养物上的表现。然后，我们评估了早期诊断耐甲氧西林金黄色葡萄球菌对经验性治疗的影响。总共纳入了 197 例金黄色葡萄球菌菌血症，其中 106 例纳入了干预组。从 MALDI-TOF MS 鉴定到 GeneXpert MRSA 结果的中位时间为 97 分钟（范围 25-250 分钟）。使用 GeneXpert MRSA 检测耐甲氧西林金黄色葡萄球菌的敏感性为 99%，特异性为 100%。干预组中不必要的耐甲氧西林金黄色葡萄球菌覆盖更少（17.1%比 29.2%，p=0.09）。当直接在阳性血培养物上进行时，GeneXpert MRSA 对耐甲氧西林金黄色葡萄球菌的诊断非常可靠。这有助于避免不必要的抗耐甲氧西林金黄色葡萄球菌药物处方，并促进在未怀疑的情况下尽早进行适当的覆盖。
