Division of Infectious Diseases, University of Calgary, 3500-26 Avenue NE, Calgary, AB, Canada T1Y 6J4.
J Infect. 2010 Sep;61(3):197-204. doi: 10.1016/j.jinf.2010.06.001. Epub 2010 Jun 12.
Time to blood culture positivity (TTP) has been suggested as a prognostic factor for adverse clinical outcome. This study describes the relationship between TTP and clinical outcome in all patients with Staphylococcus aureus bacteremia (SAB) in a large Canadian health region.
We performed a retrospective study of all first episodes of SAB occurring in the former Calgary Health Region (population approximately 1.2 million) from July 1, 2006 to December 31, 2008.
Overall, 684 cases of SAB were evaluated. The median TTP was 16 h and 31/684 (5%) cases had TTP at >48 h. Time to positivity was shorter for methicillin-susceptible Staphylococcus aureus compared with methicillin-resistant S. aureus (MRSA) and for endovascular sources compared with other sources of infection. The overall 30-day case-fatality rate was 18% (124/684). Patients with delayed TTP (>48 h) suffered the highest case-fatality rate (39%) compared to those with earlier TTP (17%; P = 0.002). Multivariable logistic regression modeling showed that age, nosocomial acquisition, MRSA, focus of infection, liver disease, and TTP < or =12 and >48 h were associated with 30-day mortality.
Although uncommon, delayed TTP may be associated with increased mortality. Empiric antimicrobial therapy should continue beyond 48 h in patients at high risk for SAB.
血培养阳性时间（TTP）已被认为是不良临床结局的预后因素。本研究描述了在加拿大一个大的卫生区域内所有金黄色葡萄球菌菌血症（SAB）患者中 TTP 与临床结局之间的关系。
我们对 2006 年 7 月 1 日至 2008 年 12 月 31 日期间在前卡尔加里卫生区域（人口约 120 万）首次发生的所有 SAB 病例进行了回顾性研究。
共评估了 684 例 SAB 病例。TTP 的中位数为 16 小时，31/684（5%）例的 TTP ＞48 小时。耐甲氧西林金黄色葡萄球菌（MRSA）与甲氧西林敏感金黄色葡萄球菌（MSSA）相比，以及血管内来源与其他感染源相比，TTP 时间更短。总体 30 天病死率为 18%（124/684）。与早期 TTP（17%；P=0.002）相比，TTP 延迟（＞48 小时）患者的病死率最高（39%）。多变量逻辑回归模型显示，年龄、医院获得性感染、MRSA、感染灶、肝病以及 TTP＜或=12 小时和＞48 小时与 30 天死亡率相关。
虽然不常见，但延迟 TTP 可能与死亡率增加有关。对于 SAB 高危患者，经验性抗菌治疗应持续超过 48 小时。
