# The impact of ampicillin and breast milk oligosaccharides on the infant microbiome and immune functions

> **NIH NIH P50** · UNIVERSITY OF CALIFORNIA, SAN DIEGO · 2024 · $202,633

## Abstract

PROJECT SUMMARY
Intrapartum antibiotic prophylaxis (IAP) of pregnant women with ampicillin (AMP) to prevent neonatal group B
Streptococcus (GBS) disease has had a major impact to reduce infection-associated morbidity and mortality in
the immediate newborn period over recent decades. However, with this reduced incidence of early-onset GBS
disease, antibiotic exposure has the potential to cause significant collateral damage by perturbing the infant gut
microbiota and its developing immune system. Breast milk, conversely, supplies the infant with oligosaccharides
that possess unique immune-modulatory (and sometimes antimicrobial) properties beneficial for shaping the
development of a normal gut microbiome. Current pediatric guidelines that recommend the use of AMP for GBS
prophylaxis and the appropriate duration of breastfeeding are now receiving significant new attention because
of their clear impacts upon the health of the infant accrued through changes, deleterious or beneficial, on the
development of a healthy microbiome and infant immune system. Co-PIs Victor Nizet and George Liu of this
Basic Science Project entitled “The impact of Ampicillin and Breast Milk Oligosaccharides on the Infant
Microbiome and Immune Functions” are pediatric physician-scientists large and successful translational
research programs built around GBS and related bacterial pathogens, antibiotic therapeutics and host immune
responses. This current proposal will apply experimental mouse models in which the labs have long standing
expertise to provide key mechanistic insights in this highly novel area of maternal-infant clinical pharmacology.
Namely, we will be studying the novel aspects of toxicology or adverse impact of empiric prophylactic antibiotic
therapy given to (millions of) mothers during pregnancy, or alternatively, to the infant afterbirth for empiric
treatment of suspected sepsis. These antibiotic exposures reduce risk of infection, but simultaneously affect the
infant microbiome and metabolome in both the short and long term, likely impacting subsequent immune
responses of the infant to infections and vaccinations. Our overarching hypothesis is that AMP, given
prophylactically to the mother or empirically to the infant, has a measurable detrimental effect on infants’ gut
microbiome and developing immune system, and consequently adversely affect the infant’s subsequent
response to bacterial infections and vaccines and the clinical pharmacology of later antibiotic administration.
Conversely, we hypothesize that maternal milk oligosaccharides (MMO) provide a benefit to the infant by
improving the resilience of the gut microbiome, consequently mitigating the antibiotic adverse effects, and
improving subsequent response to GB S infections and pneumococcal and hepatitis B vaccine responses.
Successful completion of this Basic Science Project will help determine the benefits and adverse effects of
antibiotics and MMOs on the infant microbiome and immune system and fu...

## Key facts

- **NIH application ID:** 10907653
- **Project number:** 5P50HD106463-04
- **Recipient organization:** UNIVERSITY OF CALIFORNIA, SAN DIEGO
- **Principal Investigator:** Victor Nizet
- **Activity code:** P50 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $202,633
- **Award type:** 5
- **Project period:** 2021-09-10 → 2026-07-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10907653

## Citation

> US National Institutes of Health, RePORTER application 10907653, The impact of ampicillin and breast milk oligosaccharides on the infant microbiome and immune functions (5P50HD106463-04). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10907653. Licensed CC0.

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