Understanding the gut microbiome of preterm infants

USF Health’s Christian Brechot, MD, PhD, who leads the USF Initiative on Microbiomes, speaks with Maureen Groer, PhD, Gordon Keller Professor at the USF College of Nursing, about her research on the altered gut microbiome of premature infants. | Photo by Allison Long

Maureen Groer, PhD, looks at the health of preterm infants literally from the gut. As part of  the USF Initiative on Microbiomes, Groer studies how the beneficial balance of trillions of bacteria, viruses and other microorganisms in the digestive tract – known as the gut microbiome – might be altered in prematurely born babies, and what impact it might have on their long-term health.

“As nurses, we want to do research that translates to better health care and better health outcomes,’’ she said. “And for me, that’s mothers and infants.’’

Groer is a pediatric nurse, family nurse practitioner and the Gordon Keller Professor at the USF College of Nursing. Her work examines the molecular mechanisms underlying immunology, biology and behavior and how the “crosstalk” among these systems may affect the health of infants, children and their mothers.

Funded by a grant from the National Institutes of Health (NIH), Groer studies what happens to the equilibrium of the gut microbiome of premature babies who spend weeks, or even months, in a hospital’s neonatal intensive care unit (NICU). While there, they often receive antibiotics that can lead to dysbiosis, an imbalance in the normal microbes that live in the gut. Because no two babies are alike, treatment can be complicated.

“Everybody has a signature microbiome,’’ Groer said. “We have within our body populations of bacteria, viruses and fungi that live in a relationship that’s beneficial.”

“Every NICU has its own brand of microorganisms and they’re not the natural organisms that should be populating the gut. So, these NICU babies are at risk, and that might translate into health risks later.’’

Maureen Groer, PhD, Gordon Keller Professor in the USF College of Nursing

Most healthy babies develop a balanced gut microbiome by age 3. But when infants are born too early, the evolution of the gut may be disrupted by various factors, including delivery by Cesarean section, poor organ development, and extended time in the NICU. Dysbiosis can impair an infant’s ability to gain weight, among other conditions.

Extended time in the neonatal intensive care unit may contribute to disrupted development of a premature infant’s gut.

While prenatal hospital care provides lifesaving support, babies who spend their first weeks or months there receive multiple antibiotics, undergo stressful invasive procedures, interact less with their mothers, and typically ingest more formula milk than breast milk, which would transfer the mother’s own beneficial gut bacteria to the lactating infant. As a result, Groer said “NICU babies don’t have normal microbiomes.’’

By learning more about how a person’s estimated 30 trillion bacteria influence health, aging and disease, Groer and other researchers with the Initiative on Microbiomes hope to address some of the greatest challenges in health care.

In another study, Groer is following pregnant Hispanic women who have antibodies to toxoplasmosis, a chronic infection caused by a parasite affecting more than 40 million people in the United States. A third of the women who tested positive for the infection experience adverse prenatal events, such as miscarriage or preterm birth. Groer is writing an NIH grant to fund further research on the topic, and said “it would be of interest to determine both gut and placental microbiome in this population’’ of women.

– Story by Kurt Loft