Evidence of Bacterial DNA Presence in Chorionic Villi and Amniotic Fluid in the First and Second Trimester of Pregnancy

Abstract

The sterile-womb dogma in uncomplicated pregnancy has been lively debated. Data regarding the in utero microbiome environment are based mainly on studies performed at the time of delivery. Aim: To determine whether human placenta and amniotic fluid are populated by a bacterial microbiota in the first and second trimesters of pregnancy. Materials & methods: We analyzed by next-generation sequencing method 24 and 29 samples from chorionic villus sampling (CVS) and amniocentesis (AC), respectively. The V3 region of the 16S rRNA gene was sequenced. Results: 37.5% of CVS and 14% of AC samples showed the presence of bacterial DNA. Conclusion: Our study suggests that bacterial DNA can be identified in the placenta and amniotic fluid during early prenatal life.

Does the Amniotic Fluid of Mice Contain a Viable Microbiota?

“…are resident microbiota of mammals, including humans and mice (122,(143)(144)(145). However, these microorganisms have also been identified as common bacterial DNA contaminants in studies with low microbial biomass (98,103,132). Corynebacterium spp.…”

“…Investigations of human amniotic fluid in normal pregnancy have yielded contradictory results. Multiple studies using DNA sequencing techniques (75,84,85,(96)(97)(98) and/or quantitative real-time PCR (83,97) have identified a molecular signal indicating the presence of an amniotic fluid microbiota; however, only one of these studies has demonstrated viable microorganisms from amniotic fluid through culture (75) (Supplementary Table 1). To date, no study has used cultivation, qPCR, and DNA sequencing concurrently to confirm the existence of a microbiota in human amniotic fluid during normal pregnancy.…”

“…( 103 ). Yet, very few of the prior investigations that used DNA sequencing techniques to conclude the existence of a human amniotic fluid microbiota incorporated technical controls for background DNA contamination into their analyses ( 84 , 97 , 98 , 104 , 105 ) ( Supplementary Table 1 ). Hence, there remains uncertainty as to whether the human amniotic fluid and the intra-uterine environment, in general, harbor a microbiota.…”

Leptin in the Respiratory Tract: Is There a Role in SARS-CoV-2 Infection?

“…The term “ microbiota ” identifies all microorganisms, mainly bacteria and a small number of fungi, archaea, and viruses, that live on the surface and inside our body ( D’Argenio and Salvatore, 2015 ). Most of the adult human microbiota lives in the gut but it also colonizes the oral cavity, skin, vagina, and the lung ( Dickson et al, 2016 ; Blum, 2017 ; Maschirow et al, 2019 ; Campisciano et al, 2021 ). These communities of microorganisms are essential for human physiology and survival and for this reason the microbiota is called the “forgotten organ” ( O’Hara and Shanahan, 2006 ).…”

Is a Little Enough? Paucity of Immune Proteins in Serum of Precocial Neonates of a Marine Carnivoran—the Atlantic Grey Seal

“…At birth, the neonates of viviparous mammals move abruptly from a (near) sterile environment (Perez-Munoz et al, 2017;Lim et al, 2018;Rehbinder et al, 2018;Stinson et al, 2019;Campisciano et al, 2020;Singh and Mittal, 2020) of their mothers' uteri into a world rich in potential pathogens. The survival of neonates depends on both their endogenous innate and newly engaged adaptive immune systems, and, more immediately, antibodies passively acquired from their mothers (Brambell, 1970).…”