Perinatology Research Branch, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, U.S. Department of Health and Human Services, Bethesda, MD, and Detroit, MI, USA.
Department of Obstetrics and Gynecology, Wayne State University School of Medicine, Detroit, MI, USA.
J Perinat Med. 2021 Jul 7;49(9):1103-1121. doi: 10.1515/jpm-2021-0191. Print 2021 Nov 25.
Intra-amniotic infection, defined by the presence of microorganisms in the amniotic cavity, is often accompanied by intra-amniotic inflammation. Occasionally, laboratories report the growth of bacteria or the presence of microbial nucleic acids in amniotic fluid in the absence of intra-amniotic inflammation. This study was conducted to determine the clinical significance of the presence of bacteria in amniotic fluid samples in the absence of intra-amniotic inflammation.
A retrospective cross-sectional study included 360 patients with preterm labor and intact membranes who underwent transabdominal amniocentesis for evaluation of the microbial state of the amniotic cavity as well as intra-amniotic inflammation. Cultivation techniques were used to isolate microorganisms, and broad-range polymerase chain reaction coupled with electrospray ionization mass spectrometry (PCR/ESI-MS) was utilized to detect the nucleic acids of bacteria, viruses, and fungi.
Patients whose amniotic fluid samples evinced microorganisms but did not indicate inflammation had a similar perinatal outcome to those without microorganisms or inflammation [amniocentesis-to-delivery interval (p=0.31), spontaneous preterm birth before 34 weeks (p=0.83), acute placental inflammatory lesions (p=1), and composite neonatal morbidity (p=0.8)].
The isolation of microorganisms from a sample of amniotic fluid in the absence of intra-amniotic inflammation is indicative of a benign condition, which most likely represents contamination of the specimen during the collection procedure or laboratory processing rather than early colonization or infection.
以羊膜腔内存在微生物为特征的宫内感染常伴有宫内炎症。偶尔，实验室报告羊水存在细菌生长或微生物核酸，但不存在宫内炎症。本研究旨在确定在不存在宫内炎症的情况下，羊水中存在细菌的临床意义。
一项回顾性的病例对照研究纳入了 360 例因早产胎膜完整而行经腹羊膜腔穿刺术以评估羊膜腔微生物状态和宫内炎症的患者。采用培养技术分离微生物，采用广谱聚合酶链反应结合电喷雾电离质谱（PCR/ESI-MS）检测细菌、病毒和真菌的核酸。
羊水样本中存在微生物但无炎症的患者与无微生物或无炎症的患者具有相似的围产结局[羊膜腔穿刺术至分娩的时间间隔（p=0.31）、34 周前自发性早产（p=0.83）、急性胎盘炎症病变（p=1）和复合新生儿发病率（p=0.8）]。
在不存在宫内炎症的情况下从羊水样本中分离出微生物提示为良性状态，这很可能是在采集过程或实验室处理过程中标本污染，而不是早期定植或感染。
