Antibiotic-Resistant Bacteria Found in Many Healthy Birthing Moms and Their Newborns

Study demonstrates higher rates than previously reported for high-income countries

A recent study – first of its kind in the U.S. – from Ann & Robert H. Lurie Children’s Hospital of Chicago found gut bacteria resistant to common antibiotics (ampicillin and ceftriaxone) in a sizable percentage of healthy birthing moms and their newborns. In this study, 38% of bacterial strains resistant to ceftriaxone transmitted from mother to infant were E. coli, which is a major cause of urinary and bloodstream infections, as well as meningitis in infants. Results were published in Open Forum Infectious Diseases journal.

“Perinatal transmission and early life colonization with ceftriaxone-resistant bacteria are important, since infections with these bacteria are associated with higher morbidity and healthcare costs,” said lead author Leena B. Mithal, MD, infectious diseases expert at Lurie Children’s and Associate Professor of Pediatrics at Northwestern University Feinberg School of Medicine. “Our finding that healthy pregnant people had a significant burden of these bacteria was surprising, as it was a much higher percentage than previously reported for high-income countries. It shows that this is truly a global problem with potential adverse impacts to neonatal health.”

The study enrolled healthy pregnant people during labor and their newborns, collecting 293 maternal rectal samples and 261 infant stool samples within the first 10 days of life. Ampicillin-resistant bacteria were found in 91% of mothers and 76% of infants. Ceftriaxone-resistant bacteria were found in 12% of mothers and 7% of infants. Premature births were excluded, as well as mothers who were exposed to antibiotics during pregnancy.

To confirm that the bacteria were perinatally transmitted and investigate characteristics of these bacteria, researchers performed whole genome sequencing analysis of the ceftriaxone-resistant strains.

“We found that the bacteria in the mother-infant pairs were genetically identical in most cases, which provides more proof that they are shared between mothers and infants,” said senior author Mehreen Arshad, MD, MBBS, infectious diseases researcher at Lurie Children’s and Adjunct Associate Professor of Pediatrics at Northwestern University Feinberg School of Medicine.

“Our study is unique in that it combined clinical, epidemiological and lab research,” she said. “In our future work, we are examining how long the antibiotic-resistant bacteria persist in the gut of infants, as well as how they impact infant health and overall growth,” said Dr. Arshad.

The study was funded by a Dixon Translational Research Grant and the Buffett Institute for Global Affairs Northwestern University. Additional salary support was received from National Institute of Allergy and Infectious Diseases/K23 AI139337 (L.B.M.) and K08AI123524 (M.A.). The research reported in this publication was supported, in part, by the National Institutes of Health's National Center for Advancing Translational Sciences, Grant Number UL1TR001422.

Dr. Mithal is the Neal, Kathleen and Adam Kulick Endowed Research Scholar in Neonatology at Lurie Children’s. Dr. Arshad also is an Associate Professor in Pediatrics at Aga Khan University, Karachi, Pakistan.

Ann & Robert H. Lurie Children’s Hospital of Chicago is a nonprofit organization committed to providing access to exceptional care for every child. It is the only independent, research-driven children’s hospital in Illinois and one of less than 35 nationally. This is where the top doctors go to train, practice pediatric medicine, teach, advocate, research and stay up to date on the latest treatments. Exclusively focused on children, all Lurie Children’s resources are devoted to serving their needs. Research at Lurie Children’s is conducted through Stanley Manne Children’s Research Institute, which is focused on improving child health, transforming pediatric medicine and ensuring healthier futures through the relentless pursuit of knowledge. Lurie Children’s is the pediatric training ground for Northwestern University Feinberg School of Medicine. It is ranked as one of the nation’s top children’s hospitals by U.S. News & World Report.