Researchers at Cincinnati Children's announced on March 11 that most newborns are protected from severe Escherichia coli (E. coli) infections due to antibodies passed from their mothers. The findings were published in the journal Nature and provide new insight into why only some babies become seriously ill after exposure to this common bacteria.
The study is significant because E. coli is a leading cause of severe infection in newborns, yet only about one in every 1,000 live births results in serious illness. Understanding the protective role of maternal antibodies could help doctors identify which infants are at higher risk and develop strategies for prevention.
Senior author Sing Sing Way, MD, PhD, said: "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 analyzed dried blood samples collected for routine newborn screening from 100 infants who developed E. coli infections and compared them with samples from hundreds of other infants who did not become infected. They found that antibody levels targeting E. coli were consistently lower in those who became ill.
In addition to human studies, researchers used mice raised without exposure to germs and found that introducing a probiotic strain of E. coli before pregnancy increased protective antibody production and helped shield newborn mice from infection. This probiotic strain is available under the trade name Mutaflor in Europe, Asia, and Australia.
Co-author Susana Chavez-Bueno, MD, said: "Neonatal sepsis can escalate quickly, and clinicians need better ways to identify which infants are at highest risk. These findings suggest a path toward earlier risk recognition and eventually, prevention strategies built around restoring the missing protective maternal antibodies."
Looking ahead, researchers plan to develop a screening test for identifying high-risk newborns and explore probiotics as a way to boost immunity for both mothers and their babies.
