Viral and bacterial pathogens at the maternal-fetal interface

Area of Science:

• Obstetrics and Gynecology
• Infectious Diseases
• Immunology

Background:

• Pregnancy involves complex interactions at the maternal-fetal interface.
• Understanding the incidence of infections during pregnancy is crucial for maternal and fetal health.
• Human cytomegalovirus (CMV) and herpes simplex virus (HSV) are common viral pathogens.

Purpose of the Study:

• To investigate the prevalence of pathogenic bacteria and concurrent infections with CMV and HSV types 1 and 2.
• To analyze the distribution of these pathogens in placental and decidual tissues across trimesters.
• To explore the potential role of immune responses in managing these infections.

Main Methods:

• Polymerase chain reaction (PCR) analysis of biopsy samples from placenta and decidua.
• Detection of selected bacteria and viruses (CMV, HSV-1, HSV-2).
• Analysis of immunoglobulin G (IgG) in placental samples.

Main Results:

• 38% of placental samples tested positive for bacteria and viruses.
• CMV, HSV-1, and HSV-2 were detected, alone or with bacteria, in first and second trimesters.
• Specific bacteria (Ureaplasma urealyticum, Mycoplasma hominis, Gardnerella/Bifidobacterium) were more prevalent in the second trimester.
• Viruses were more frequently detected in first-trimester decidua than placenta, while bacteria were more common in the placenta.
• Placental IgG levels suggested immune suppression of CMV reactivation in the presence of bacteria.

Conclusions:

• Pathogenic bacteria and viruses are frequently detected in placental tissues during pregnancy.
• The distribution of pathogens differs between placental and decidual tissues and across trimesters.
• Maternal immune responses, indicated by IgG, may play a role in controlling CMV reactivation during co-infections with bacteria.