Eli and Edythe Broad Center of Regeneration Medicine, University of California, San Francisco, California, United States of America.
Department of Surgery, University of California, San Francisco, California, United States of America.
PLoS One. 2020 Apr 15;15(4):e0231239. doi: 10.1371/journal.pone.0231239. eCollection 2020.
Chorioamnionitis has been linked to spontaneous preterm labor and complications such as neonatal sepsis. We hypothesized that microbial cell-free (cf) DNA would be detectable in maternal plasma in patients with chorioamnionitis and could be the basis for a non-invasive method to detect fetal exposure to microorganisms.
The purpose of this study was to determine whether next generation sequencing could detect microbial cfDNA in maternal plasma in patients with chorioamnionitis.
Maternal plasma (n = 94) and umbilical cord plasma (n = 120) were collected during delivery at gestational age 28-41 weeks. cfDNA was extracted and sequenced. Umbilical cord plasma samples with evidence of contamination were excluded. The prevalence of microorganisms previously implicated in choriomanionitis, neonatal sepsis and intra-amniotic infections, as described in the literature, were examined to determine if there was enrichment of these microorganisms in this cohort. Specific microbial cfDNA associated with chorioamnionitis was first detected in umbilical cord plasma and confirmed in the matched maternal plasma samples (n = 77 matched pairs) among 14 cases of histologically confirmed chorioamnionitis and one case of clinical chorioamnionitis; 63 paired samples were used as controls. A correlation of rank of a given microorganism across maternal plasma and matched umbilical cord plasma was used to assess whether signals found in umbilical cord plasma were also present in maternal plasma.
Microbial DNA sequences associated with clinical and/or histological chorioamnionitis were enriched in maternal plasma in cases with suspected chorioamnionitis when compared to controls (12/14 microorganisms, p = 0.02). Analysis of the microbial cfDNA in umbilical cord plasma among the 1,251 microorganisms detectable with this assay identified Streptococcus mitis, Ureaplasma spp., and Mycoplasma spp. in cases of suspected chorioamnionitis. This assay also detected cfDNA from Lactobacillus spp. in controls. Comparison between maternal plasma and umbilical cord plasma confirmed these signatures were also present in maternal plasma. Unbiased analysis of microorganisms with significantly correlated signal between matched maternal plasma and umbilical cord plasma identified the above listed 3 microorganisms, all of which have previously been implicated in patients with chorioamnionitis (Mycoplasma hominis p = 0.0001; Ureaplasma parvum p = 0.002; Streptococcus mitis p = 0.007). These data show that the pathogen signal relevant for chorioamnionitis can be identified in both maternal and umbilical cord plasma.
This is the first report showing the detection of relevant microbial cell-free cfDNA in maternal plasma and umbilical cord plasma in patients with clinical and/or histological chorioamnionitis. These results may lead to the development of a specific assay to detect perinatal infections for targeted therapy to reduce early neonatal sepsis complications.
绒毛膜羊膜炎与自发性早产和新生儿败血症等并发症有关。我们假设在患有绒毛膜羊膜炎的患者的母体外周血中可以检测到微生物无细胞（cf）DNA，并且可以作为一种非侵入性方法来检测胎儿暴露于微生物。
本研究旨在确定下一代测序是否可以检测到患有绒毛膜羊膜炎的患者的母体外周血中的微生物 cfDNA。
在 28-41 孕周分娩时采集母体外周血（n = 94）和脐静脉血（n = 120）。提取和测序 cfDNA。排除有污染证据的脐静脉血样本。检查了以前文献中描述的与绒毛膜羊膜炎、新生儿败血症和羊膜内感染有关的微生物的流行情况，以确定在该队列中是否存在这些微生物的富集。在 14 例组织学证实的绒毛膜羊膜炎和 1 例临床绒毛膜羊膜炎病例中，首先在脐静脉血中检测到与绒毛膜羊膜炎相关的特定微生物 cfDNA，并在 77 对匹配的母体外周血样本中得到证实（n = 77 对匹配）；63 对配对样本用作对照。使用给定微生物在母体外周血和匹配的脐静脉血中的等级的相关性来评估在脐静脉血中发现的信号是否也存在于母体外周血中。
与对照组相比，在疑似绒毛膜羊膜炎的病例中，与临床和/或组织学绒毛膜羊膜炎相关的微生物 DNA 序列在母体外周血中富集（14 例中的 12 种微生物，p = 0.02）。对可通过该检测方法检测到的 1251 种微生物的脐静脉血浆中的微生物 cfDNA 进行分析，在疑似绒毛膜羊膜炎病例中鉴定出缓症链球菌、解脲脲原体和支原体。该检测还在对照组中检测到乳酸杆菌 cfDNA。母体外周血和脐静脉血之间的比较证实这些特征也存在于母体外周血中。对匹配的母体外周血和脐静脉血之间信号具有显著相关性的微生物进行无偏分析，确定了上述列出的 3 种微生物，所有这些微生物以前都与绒毛膜羊膜炎患者有关（解脲脲原体 p = 0.0001；微小脲原体 p = 0.002；缓症链球菌 p = 0.007）。这些数据表明，与绒毛膜羊膜炎相关的病原体信号可以在母体外周血和脐静脉血中识别。
这是第一个报道在患有临床和/或组织学绒毛膜羊膜炎的患者的母体外周血和脐静脉血中检测到相关微生物无细胞（cf）DNA 的报告。这些结果可能导致开发一种特定的检测方法来检测围产期感染，以进行靶向治疗，从而减少新生儿早期败血症的并发症。
