Researchers at Cincinnati Children’s announced on Apr. 17 that a multi-center study has found that most newborns are protected from severe Escherichia coli (E. coli) infections by antibodies passed from their mothers during pregnancy. The findings, published in the journal Nature on March 11, help explain why only a small number of babies become seriously ill from this common bacteria.
The study matters because E. coli is present in nearly all people and is a leading cause of severe infection in newborns, yet only about one in every 1,000 live births results in serious illness. Understanding how immunity is transferred could help prevent life-threatening infections among infants.
According to senior author Sing Sing Way, MD, PhD, “This helps explain a long-standing question: if most babies are exposed to germs soon after birth, why don’t even more develop severe infection? Our findings provide a key missing piece to this puzzle — the antibodies stimulated by the presence of these common bacteria in our intestines protect us against infection. In pregnancy, the natural transfer of these germ-fighting antibodies from mothers to babies in the womb protect the vast majority against infection. In the rare situation when these antibodies are low in mothers or inefficiently transferred, babies are at much higher risk for infection.”
The research team included scientists from Cincinnati Children’s, University of Queensland (Australia), University of Texas Southwestern Medical Center, Children’s Mercy Kansas City and University of Missouri Kansas City School of Medicine. They compared dried blood samples collected for routine newborn screening between infants who developed E. coli infections and those who did not and found consistently lower levels of protective antibodies among infected babies.
Mouse studies supported these findings by showing that introducing a probiotic strain called Nissle 1917 before pregnancy increased protective antibody production and protected offspring against infection. Mark Schembri, BSc, PhD said: “Understanding protection takes both types of evidence – what we can evaluate from specimens in human babies that naturally develop infection, and what we can test by experimentally causing infection.”
Susana Chavez-Bueno, MD stated: “Neonatal sepsis can escalate quickly, and doctors need better ways to identify which infants are at highest risk. These findings suggest a path toward earlier risk recognition and prevention strategies built around restoring the missing protective maternal antibodies.”
Looking ahead, researchers plan to develop screening tests for high-risk newborns as well as probiotics safe for use during pregnancy that could strengthen both maternal immunity and protection passed on to infants.
