Shah Samir S, Downes Kevin J, Elliott Michael R, Bell Louis M, McGowan Karin L, Metlay Joshua P
Children's Hospital of Philadelphia, Division of Infectious Diseases, Room 1526, North Campus, 34th Street and Civic Center Boulevard, Philadelphia, PA 19104, USA.
Pediatrics. 2008 Jan;121(1):135-41. doi: 10.1542/peds.2007-1387.
Children with central venous catheters and suspected bloodstream infection are often hospitalized for 48 hours to receive empiric antibiotic therapy pending blood-culture results. Continuous monitoring blood-culture systems allow for more rapid detection of bloodstream infection than previous blood-culture systems, a feature that may facilitate earlier determination of the true presence or absence of bloodstream infection and shorten empiric antibiotic therapy and duration of hospitalization.
This retrospective cohort study included children with central venous catheters who were diagnosed with laboratory-confirmed bloodstream infection after evaluation in the ambulatory care setting.
Two-hundred episodes of bloodstream infection were included. The median patient age was 5.5 years. Central venous catheters were in place for a median of 80.5 days. Gram-negative bacteria accounted for 51% of infections as part of either a monomicrobial (25%) or polymicrobial (26%) infection. The overall median time to blood-culture positivity was 14 hours. The predicted probability for a culture being positive at 36 hours was 99.2% for infections caused by gram-negative bacteria and 96.6% for any infection after adjusting for age, catheter type, and recent antibiotic use. In a multivariate Cox proportional-hazards regression model, polymicrobial infections with > or = 1 gram-negative bacteria and monomicrobial infections caused by gram-negative bacteria were independently associated with an earlier time to blood-culture positivity after adjusting for age, catheter type, and recent antibiotic use.
The time to blood-culture positivity depends on bacterial category. Bloodstream infections caused by gram-negative bacteria are detected most quickly. Our data suggest that discontinuation of empiric antibiotic coverage may be warranted in clinically stable children with central venous catheters if the blood-culture results remain negative 24 to 36 hours after collection.
患有中心静脉导管且疑似血流感染的儿童通常需住院48小时，以便在血培养结果出来之前接受经验性抗生素治疗。与以往的血培养系统相比，连续监测血培养系统能够更快速地检测出血流感染，这一特性可能有助于更早地确定血流感染的实际有无，缩短经验性抗生素治疗时间和住院时长。
这项回顾性队列研究纳入了在门诊护理环境中接受评估后被诊断为实验室确诊血流感染的中心静脉导管患儿。
共纳入200例血流感染病例。患者中位年龄为5.5岁。中心静脉导管留置的中位时间为80.5天。革兰氏阴性菌占感染病例的51%，其中单一微生物感染占25%，多微生物感染占26%。血培养呈阳性的总体中位时间为14小时。在调整年龄、导管类型和近期抗生素使用情况后，革兰氏阴性菌引起的感染在36小时时培养呈阳性的预测概率为99.2%，任何感染的预测概率为96.6%。在多变量Cox比例风险回归模型中，在调整年龄、导管类型和近期抗生素使用情况后，含有≥1种革兰氏阴性菌的多微生物感染和革兰氏阴性菌引起的单一微生物感染与血培养阳性时间较早独立相关。
血培养呈阳性的时间取决于细菌类别。革兰氏阴性菌引起的血流感染检测最快。我们的数据表明，如果采集血培养24至36小时后结果仍为阴性，对于临床稳定的中心静脉导管患儿，可能有必要停止经验性抗生素覆盖。
