Kuperman Amir Asher*, Zimmerman Alex, Hamadia Suha, Gurevich Slava, Fichtman Boris, Gavert Nancy, Shental Noam, Straussman Ravid, Rechnitzer Hagai, Shvalb Sergio, Haviv Izhak, Yagel Simcha, Koren Omry.
*Blood coagulation service and pediatric hematology clinic, Galilee medical center, Nahariya, Israel. Faculty of medicine in the Galilee,Bar-Ilan University, Safed, Israel
Introduction: Since 1900 the consensus is that the fetus is shielded from bacteria in-utero. In the last years the classic perception has changed, and studies started to point that bacteria exist in the placenta and fetus. In the last 2 years, the pendulum is swinging back to the “sterile fetus” hypothesis. The aim of this study is to investigate for the presence of placental bacteria using several methods in parallel. If bacteria are detected, we will attempt to link their presence with pregnancy complications.
Materials and methods: Eighty-five placentas were collected (17 from preeclampsia, 4 from intrauterine growth retardation, and 64 controls), in cesarean sections, in 2 medical centers. All the placentas and “environmental controls” were placed in culture media. Four placentas were chosen (2 PET and 2 from the control group), and Gram stain, immunohistochemistry for bacteria, electron microscopy, 16S rRNA gene amplification and TaqMan RT PCR were performed on 7 representative points. Metagenomics was performed on another control placenta.
Results: Some of the placental and environmental cultures grew bacteria, but other methods did not show any bacteria, besides immunohistochemistry (0-3 bacteria per slide). No correlation was found between bacteria in culture or in immunohistochemistry with any parameter tested. Metagenomics on a control placenta revealed only skin bacteria that are suspected to be contaminants.
Conclusions: Based on these results, it seems that the fetus is sterile in-utero, and acquires bacteria during and after delivery. Furthermore, the results negate the potential involvement of bacteria, as the common etiology of pre-eclampsia.