Department of Clinical Laboratory, The Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou, Zhejiang Province, China.
Department of Clinical Laboratory, The Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou, Zhejiang Province, China.
J Microbiol Methods. 2020 May;172:105894. doi: 10.1016/j.mimet.2020.105894. Epub 2020 Mar 14.
The rapid diagnosis of bloodstream infection (BSI) often leads to better clinical outcomes. The present study was conducted to compare two rapid protocols (Sepsityper kit and short-term subculture) for matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS)-based identification of microorganisms from positive blood cultures in pediatric patients.
This study was conducted between May 1, 2018, and April 30, 2019, at a tertiary children's hospital in eastern China. Only monomicrobial blood cultures included in this study were used to conduct the Sepsityper kit protocol and short-term subculture protocol at the same time.
In total, 115 monomicrobial blood cultures were included in this study. For the Sepsityper kit protocol, 85.2% and 64.3% of microorganisms were correctly identified to the genus (score ≥ 1.700) and species levels (score ≥ 2.000), respectively. For the short-term subculture protocol, 89.6% and 70.4% of microorganisms were correctly identified to the genus and species levels, respectively. At the genus level (P = .321) or the species level (P = .325), there was no significant difference between the Sepsityper kit protocol and the short-term subculture protocol. Moreover, the short-term subculture protocol exhibited similar performance between Gram-positive bacteria (GPB) and Gram-negative bacteria (GNB) (the genus level: 93.7% (GPB) versus 87.9% (GNB), P = .518; the species level: 68.4% (GPB) versus 81.8% (GNB), P = .147). In addition, the Sepsityper kit protocol exhibited similar performance between GPB and GNB at the genus level (86.1% (GPB) versus 84.8% (GNB), P = 1.000). However, the Sepsityper kit protocol exhibited better performance in GNB at the species level (58.2% (GPB) versus 81.8% (GNB), P = .017). The rates of yeast-like fungi were correctly identified to the genus level (0.0%) or the species level (0.0%) for short-term subculture protocol were significantly lower than those of other microorganisms (the genus level: 92.0%, P = .001; the species level: 72.3%, P = .024). However, a similar result of identification was not found using the Sepsityper kit protocol (the genus level: P = .384; the species level: P = .599). In addition, the two rapid protocols both exhibited better performance at the genus level when the time to positivity (TTP) of blood cultures <19 h (the Sepsityper kit protocol: 91.8% (TTP < 19 h) versus 77.8% (TTP ≥ 19 h), P = .034; the short-term subculture protocol: 95.1% (TTP < 19 h) versus 83.3% (TTP ≥ 19 h), P = .040). In addition, the two rapid protocols both exhibited better performance at the species level when the TTP of blood cultures was <19 h (the Sepsityper kit protocol: 78.7% (TTP < 19 h) versus 48.1% (TTP ≥ 19 h), P = .000; the short-term subculture protocol: 83.6% (TTP < 19 h) versus 55.6% (TTP ≥ 19 h), P = .001).
The Sepsityper kit protocol and short-term subculture protocol are both reliable and rapid methods for the identification of most microorganisms from positive blood cultures in pediatric patients. The performance of these two rapid protocols is associated with the TTP of blood cultures.
快速诊断血流感染（BSI）通常可带来更好的临床结局。本研究旨在比较两种快速方案（Sepsityper 试剂盒和短期亚培养）用于基于基质辅助激光解吸/电离飞行时间质谱（MALDI-TOF MS）鉴定儿科患者阳性血培养中的微生物。
本研究于 2018 年 5 月 1 日至 2019 年 4 月 30 日在我国东部的一家三级儿童医院进行。仅纳入本研究中单一致病菌的血培养同时进行 Sepsityper 试剂盒方案和短期亚培养方案。
本研究共纳入 115 份单一致病菌血培养。对于 Sepsityper 试剂盒方案，85.2%和 64.3%的微生物分别正确鉴定到属（评分≥1.700）和种（评分≥2.000）水平。对于短期亚培养方案，89.6%和 70.4%的微生物分别正确鉴定到属和种水平。在属水平（P=0.321）或种水平（P=0.325），Sepsityper 试剂盒方案与短期亚培养方案之间无显著差异。此外，短期亚培养方案在革兰阳性菌（GPB）和革兰阴性菌（GNB）之间表现出相似的性能（属水平：93.7%（GPB）与 87.9%（GNB），P=0.518；种水平：68.4%（GPB）与 81.8%（GNB），P=0.147）。此外，Sepsityper 试剂盒方案在属水平上对 GPB 和 GNB 表现出相似的性能（86.1%（GPB）与 84.8%（GNB），P=1.000）。然而，Sepsityper 试剂盒方案在 GNB 种水平上的表现更好（58.2%（GPB）与 81.8%（GNB），P=0.017）。短期亚培养方案鉴定酵母样真菌的种水平的正确率（0.0%）明显低于其他微生物（属水平：92.0%，P=0.001；种水平：72.3%，P=0.024）。然而，使用 Sepsityper 试剂盒方案并未发现类似的鉴定结果（属水平：P=0.384；种水平：P=0.599）。此外，当血培养的阳性时间（TTP）<19 小时时，两种快速方案在属水平上的表现均更好（Sepsityper 试剂盒方案：91.8%（TTP<19 小时）与 77.8%（TTP≥19 小时），P=0.034；短期亚培养方案：95.1%（TTP<19 小时）与 83.3%（TTP≥19 小时），P=0.040）。此外，当血培养的 TTP<19 小时时，两种快速方案在种水平上的表现均更好（Sepsityper 试剂盒方案：78.7%（TTP<19 小时）与 48.1%（TTP≥19 小时），P=0.000；短期亚培养方案：83.6%（TTP<19 小时）与 55.6%（TTP≥19 小时），P=0.001）。
Sepsityper 试剂盒方案和短期亚培养方案都是鉴定儿科患者阳性血培养中大多数微生物的可靠且快速的方法。这两种快速方案的性能与血培养的 TTP 相关。
