A common type of bacteria, carried by many women, has been linked with premature delivery and stillbirths. This understanding may help to reduce the number of deaths. Researchers have found that Group B Streptococcus (GBS) bacteria, which occur in the vagina of 20 to 30 percent of women, are associated with stillbirths. The findings come from a study conducted using mice.
Group B Streptococcus infection is the infection caused by the bacterium Streptococcus agalactiae. In general, GBS is a harmless commensal (a relationships between two organisms) bacterium being part of the human microbiota colonizing the gastrointestinal and genitourinary tracts. However, in some cases the bacterium can cause an infection that can result in the death of a newborn baby. There is around a one in 200 chance of that happening, according to infectious diseases expert Professor Sanjaya Senanayake from the Australian National University (ANU).
This much has been known for several years, what is new is the connection between GBS and stillbirths and premature delivery. This is the subject of the new research performed at the Indian Institute of Technology – Bombay.
The finding is the result of observational studies. When scientists examined the placenta of mice, that had been infected with GBS and after a stillbirth had occurred, inflammation was observed. The situation was created by the amniotic sac in the pregnant mice being deliberately infected with GBS at day 18 of the pregnancy.
Correlating this with detection of GBS, commentating microbiologist Professor Sanjaya Senanayake from the Australian National University explains: "What these scientists are saying is that they found the bug, that can cause problems in newborns, can produce these little packets of inflammation and without moving from the vagina can send these packets of inflammation into the womb and can cause induced premature labour and stillbirths.”.
The findings help to explain why with some cases of stillbirths and premature babies inflammation is observed under the microscope but the bacteria are not detected. The implications of the research could affect testing, monitoring for and management of GBS during pregnancy.
The research has been published in the journal PLOS Pathogens in a paper headed “Membrane Vesicles of Group B Streptococcus Disrupt Feto-Maternal Barrier Leading to Preterm Birth.”