Division of Neonatology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
Department of Pediatrics, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA.
Arch Dis Child Fetal Neonatal Ed. 2022 Nov;107(6):583-588. doi: 10.1136/archdischild-2021-323416. Epub 2022 Mar 10.
To determine the time to positivity (TTP) of blood cultures among infants with late-onset bacteraemia and predictors of TTP >36 hours.
Retrospective cohort study.
16 birth centres in two healthcare systems.
Infants with positive blood cultures obtained >72 hours after birth.
The main outcome was TTP, defined as the time interval from specimen collection to when a neonatal provider was notified of culture growth. TTP analysis was restricted to the first positive culture per infant. Patient-specific and infection-specific factors were analysed for association with TTP >36 hours.
Of 10 235 blood cultures obtained from 3808 infants, 1082 (10.6%) were positive. Restricting to bacterial pathogens and the first positive culture, the median TTP (25th-75th percentile) for 428 cultures was 23.5 hours (18.4-29.9); 364 (85.0%) resulted in 36 hours. Excluding coagulase-negative staphylococci (CoNS), 275 of 294 (93.5%) cultures were flagged positive by 36 hours. In a multivariable model, CoNS isolation and antibiotic pretreatment were significantly associated with increased odds of TTP >36 hours. Projecting a 36-hour empiric duration at one site and assuming that all negative evaluations were associated with an empiric course of antibiotics, we estimated that 1164 doses of antibiotics would be avoided in 629 infants over 10 years, while delaying a subsequent antibiotic dose in 13 infants with bacteraemia.
Empiric antibiotic administration in late-onset infection evaluations (not targeting CoNS) can be stopped at 36 hours. Longer durations (48 hours) should be considered when there is pretreatment or antibiotic therapy is directed at CoNS.
确定晚发型菌血症婴儿血培养的阳性时间（TTP）和 TTP＞36 小时的预测因素。
回顾性队列研究。
两个医疗系统中的 16 个分娩中心。
出生后＞72 小时获得阳性血培养的婴儿。
主要结局是 TTP，定义为从标本采集到通知新生儿提供者培养物生长的时间间隔。TTP 分析仅限于每个婴儿的第一次阳性培养。分析了患者特异性和感染特异性因素与 TTP＞36 小时的关系。
在从 3808 名婴儿中获得的 10235 份血培养中，有 1082 份（10.6%）为阳性。将细菌病原体和第一次阳性培养限制在研究范围内，428 份培养物的中位数 TTP（25 至 75 百分位数）为 23.5 小时（18.4-29.9）；364 份（85.0%）在 36 小时内得到阳性结果。不包括凝固酶阴性葡萄球菌（CoNS），294 份培养物中有 275 份（93.5%）在 36 小时内被标记为阳性。在多变量模型中，CoNS 分离和抗生素预处理与 TTP＞36 小时的可能性增加显著相关。假设在一个地点进行 36 小时的经验性治疗，并且所有阴性评估都与经验性抗生素治疗相关，我们估计在 10 年内，629 名婴儿可以避免 1164 剂抗生素，而在 13 名患有菌血症的婴儿中延迟后续抗生素剂量。
在晚发型感染评估中（不针对 CoNS），可以在 36 小时停止经验性抗生素治疗。当存在预处理或抗生素治疗针对 CoNS 时，应考虑更长的持续时间（48 小时）。
