Irene Sterpu1, Emma Fransson2, Luisa W Hugerth3, Juan Du4, Marcela Pereira4, Liqin Cheng4, Sebastian Alexandru Radu4, Lorena Calderón-Pérez5, Yinghua Zha4, Pia Angelidou4, Alexandra Pennhag4, Fredrik Boulund3, Annika Scheynius6, Lars Engstrand3, Eva Wiberg-Itzel1, Ina Schuppe-Koistinen7. 1. Department of Clinical Science and Education, and Division of Obstetrics and Gynaecology, Department of Clinical Science, Intervention and Technology, Karolinska Institute, Södersjukhuset, Stockholm, Sweden. 2. Centre for Translational Microbiome Research, Department of Microbiology, Tumor and Cell Biology, Karolinska Institute, Stockholm, Sweden; Department of Women's and Children's Health, Uppsala University, Uppsala, Sweden. 3. Centre for Translational Microbiome Research, Department of Microbiology, Tumor and Cell Biology, Karolinska Institute, Stockholm, Sweden; Science for Life Laboratory, Karolinska Institutet, Stockholm, Sweden. 4. Centre for Translational Microbiome Research, Department of Microbiology, Tumor and Cell Biology, Karolinska Institute, Stockholm, Sweden. 5. Centre for Translational Microbiome Research, Department of Microbiology, Tumor and Cell Biology, Karolinska Institute, Stockholm, Sweden; Eurecat, Centre Tecnològic de Catalunya, Unitat de Nutrició i Salut, Reus, Spain. 6. Science for Life Laboratory, Karolinska Institutet, Stockholm, Sweden; Department of Clinical Science and Education, Karolinska Institutet, and Sachs' Children and Youth Hospital, Södersjukhuset, Stockholm, Sweden. 7. Centre for Translational Microbiome Research, Department of Microbiology, Tumor and Cell Biology, Karolinska Institute, Stockholm, Sweden; Science for Life Laboratory, Karolinska Institutet, Stockholm, Sweden. Electronic address: ina.schuppe.koistinen@ki.se.
Abstract
BACKGROUND: The placenta plays an important role in the modulation of pregnancy immunity; however, there is no consensus regarding the existence of a placental microbiome in healthy full-term pregnancies. OBJECTIVE: This study aimed to investigate the existence and origin of a placental microbiome. STUDY DESIGN: A cross-sectional study comparing samples (3 layers of placental tissue, amniotic fluid, vernix caseosa, and saliva, vaginal, and rectal samples) from 2 groups of full-term births: 50 women not in labor with elective cesarean deliveries and 26 with vaginal deliveries. The comparisons were performed using polymerase chain reaction amplification and DNA sequencing techniques and bacterial culture experiments. RESULTS: There were no significant differences regarding background characteristics between women who delivered by elective cesarean and those who delivered vaginally. Quantitative measurements of bacterial content in all 3 placental layers (quantitative polymerase chain reaction of the 16S ribosomal RNA gene) did not show any significant difference among any of the sample types and the negative controls. Here, 16S ribosomal RNA gene sequencing of the maternal side of the placenta could not differentiate between bacteria in the placental tissue and contamination of the laboratory reagents with bacterial DNA. Probe-specific quantitative polymerase chain reaction for bacterial taxa suspected to be present in the placenta could not detect any statistically significant difference between the 2 groups. In bacterial cultures, substantially more bacteria were observed in the placenta layers from vaginal deliveries than those from cesarean deliveries. In addition, 16S ribosomal RNA gene sequencing of bacterial colonies revealed that most of the bacteria that grew on the plates were genera typically found in human skin; moreover, it revealed that placentas delivered vaginally contained a high prevalence of common vaginal bacteria. Bacterial growth inhibition experiments indicated that placental tissue may facilitate the inhibition of bacterial growth. CONCLUSION: We found no evidence to support the existence of a placental microbiome in our study of 76 term pregnancies, which used polymerase chain reaction amplification and sequencing techniques and bacterial culture experiments. Incidental findings of bacterial species could be due to contamination or to low-grade bacterial presence in some locations; such bacteria do not represent a placental microbiome per se.
BACKGROUND: The placenta plays an important role in the modulation of pregnancy immunity; however, there is no consensus regarding the existence of a placental microbiome in healthy full-term pregnancies. OBJECTIVE: This study aimed to investigate the existence and origin of a placental microbiome. STUDY DESIGN: A cross-sectional study comparing samples (3 layers of placental tissue, amniotic fluid, vernix caseosa, and saliva, vaginal, and rectal samples) from 2 groups of full-term births: 50 women not in labor with elective cesarean deliveries and 26 with vaginal deliveries. The comparisons were performed using polymerase chain reaction amplification and DNA sequencing techniques and bacterial culture experiments. RESULTS: There were no significant differences regarding background characteristics between women who delivered by elective cesarean and those who delivered vaginally. Quantitative measurements of bacterial content in all 3 placental layers (quantitative polymerase chain reaction of the 16S ribosomal RNA gene) did not show any significant difference among any of the sample types and the negative controls. Here, 16S ribosomal RNA gene sequencing of the maternal side of the placenta could not differentiate between bacteria in the placental tissue and contamination of the laboratory reagents with bacterial DNA. Probe-specific quantitative polymerase chain reaction for bacterial taxa suspected to be present in the placenta could not detect any statistically significant difference between the 2 groups. In bacterial cultures, substantially more bacteria were observed in the placenta layers from vaginal deliveries than those from cesarean deliveries. In addition, 16S ribosomal RNA gene sequencing of bacterial colonies revealed that most of the bacteria that grew on the plates were genera typically found in human skin; moreover, it revealed that placentas delivered vaginally contained a high prevalence of common vaginal bacteria. Bacterial growth inhibition experiments indicated that placental tissue may facilitate the inhibition of bacterial growth. CONCLUSION: We found no evidence to support the existence of a placental microbiome in our study of 76 term pregnancies, which used polymerase chain reaction amplification and sequencing techniques and bacterial culture experiments. Incidental findings of bacterial species could be due to contamination or to low-grade bacterial presence in some locations; such bacteria do not represent a placental microbiome per se.
Authors: Valeria Garcia-Flores; Roberto Romero; Yi Xu; Kevin Theis; Marcia Arenas-Hernandez; Derek Miller; Azam Peyvandipour; Jose Galaz; Dustyn Levenson; Gaurav Bhatti; Meyer Gershater; Errile Pusod; David Kracht; Violetta Florova; Yaozhu Leng; Li Tao; Megan Faucett; Robert Para; Chaur-Dong Hsu; Gary Zhang; Adi L Tarca; Roger Pique-Regi; Nardhy Gomez-Lopez Journal: Res Sq Date: 2021-03-31
Authors: Simone Bihl; Marcus de Goffau; Daniel Podlesny; Nicola Segata; Fergus Shanahan; Jens Walter; W Florian Fricke Journal: Gut Microbes Date: 2022 Jan-Dec
Authors: Andrew D Winters; Roberto Romero; Jonathan M Greenberg; Jose Galaz; Zachary D Shaffer; Valeria Garcia-Flores; David J Kracht; Nardhy Gomez-Lopez; Kevin R Theis Journal: Front Immunol Date: 2022-02-28 Impact factor: 7.561