EHJ：持续感染致感染性心内膜炎患者死亡率增高

临床实践中，抗生素治疗常常不能有效控制感染性心内膜炎病程，进而导致患者死于心衰、血栓、严重败血症或完全性房室传导阻滞的风险增高。根据欧洲指南，这种不能控制的感染包括持续感染，定义为抗生素治疗7-10天后出现发热和持续性血培养阳性。然而，这个分界有点武断，时间可能更长。来自西班牙的一研究小组近期发现左侧感染性心内膜炎在抗生素治疗开始48-72小时后持续性血培养阳性与患者院内死亡率增高密切相关，发表在《欧洲心脏杂志》上。

本研究受试者为1996年至2011年间692例被诊断为左侧感染性心内膜炎的患者，其中407位在经抗生素治疗开始的48-72小时后重复进行血液培养。我们对比了血培养结果阴性和持续阳性患者的档案。采用多因素logistic回归模型分析明确持续血培养阳性与预后的关系。入院时血培养阳性的256例患者中，其中89例（35%）是持续性血培养阳性的。结果表明持续血培养阳性（OR: 2.1; 95% 可信区间: 1.2-3.6）、年龄（OR: 1.026; 95% 可信区间: 1.007-1.046）、金黄色葡萄球菌感染（OR: 3.3; 95% 可信区间: 1.6-6.6）、心衰（OR: 2.8; 95% 可信区间: 1.6-4.7）和肾衰竭（OR: 2.9; 95% 可信区间: 1.8-4.9）与左侧感染性心内膜炎患者院内死亡率增高独立相关。

持续血培养阳性是左侧感染性心内膜炎患者院内死亡率高发的独立危险因素。因此，治疗该类患者时应该考虑危险分级。由于本课题为回顾性研究，更多地数据支持需要前瞻性研究。

Prognostic role of persistent positive blood cultures after initiation of antibiotic therapy in left-sided infective endocarditis
Aim
Persistent infection is not a scientific evidence-based definition. The guidelines of infective endocarditis (IE) establish a cut-off point of 7–10 days, which is arbitrary and probably too long. Our hypothesis is that persistent positive blood cultures after 48–72 h from the initiation of antibiotic therapy are associated with a worse prognosis in patients with left-sided IE.
Methods and results
We repeated blood cultures after 48–72 h of the initiation of the antibiotic treatment in 407 patients with left-sided IE of a total of 692 episodes consecutively diagnosed from 1996 to 2011. We have compared the profile of patients whose blood cultures became negative and those with persistent positive blood cultures. We performed a multivariate logistic regression model to determine the prognostic implication of persistent positive blood cultures.
Of 256 patients with positive blood cultures at admission, 89 (35%) had persistent positive cultures after 48–72 h from the initiation of the antibiotic treatment. Persistent positive blood cultures (OR: 2.1; 95% CI: 1.2–3.6), age (OR: 1.026; 95% CI: 1.007–1.046), Staphylococcus aureus infection (OR: 3.3; 95% CI: 1.6–6.6), heart failure (OR: 2.8; 95% CI: 1.6–4.7), and renal failure (OR: 2.9; 95% CI: 1.8–4.9) were found to be independently associated with higher in-hospital mortality.
Conclusions
The presence of persistent positive blood cultures is an independent risk factor for in-hospital mortality which doubles the risk of death of patients with left-sided IE. It should be taken into account in the risk stratification of these patients.