# Coordinated growth in microbial communities and implications for antibiotic sensitivities

> **NIH NIH F32** · CARNEGIE INSTITUTION OF WASHINGTON, D.C. · 2024 · $76,756

## Abstract

Project Summary
The discovery of antibiotics greatly decreased the public health burden associated with bacterial infections;
however, antibiotics also disrupt the beneficial microbiome. An added challenge is that the efficacy of
treatments is often not what is seen in the laboratory setting in part due to the fact bacteria live in mixed
microbial populations. While some mechanisms of community protection have been well studied such as
degradation or sequestration of the antibiotic, significantly less effort has gone into understanding the ways
that physiological changes protect the cells. Efforts to study mixed microbial systems often use synthetic
communities where interactions are dominated by nutrient competition and stress response pathways. To
address these issues, our laboratory uses a naturally formed community of lactic acid bacteria and Acetobacter
that is highly reproducible form natural environments and displays coevolved properties. Recently we have
shown that the beneficial microbe Lactiplantibacillus plantarum has a difference in antibiotic sensitivities when
grown in a mixed microbial community with Acetobacter species compared to when it is grown as an isolated
strain. Previous work has focused on how these microbes engage in cross feeding; however little work has
gone into understanding how non-nutritional cues might affect cellular physiology. My research aims to close
this gap by understanding how L. plantarum and Acetoabcter coordinate growth to modify physiology
and sensitivity to antibiotics. Leveraging the chemically defined media I co-created, I have recapitulated this
antibiotic sensitivity change with the addition of the small molecule acetate which is produced by Acetobacter.
Additionally, I have seen that acetate stimulates the growth of L. plantarum. This work led me to identify a
mutant of L. plantarum that can grow fast without the stimulation of acetate. Through a combination of genetic,
metabolomic, and microscopic approaches I will identify the underlying molecular mechanism of the
phenotype. This project will identify how a cross-phylum signals affect cellular physiology which may have
implications across bacterial species to understanding how antibiotic sensitives are modulated by mixed
microbial communities.

## Key facts

- **NIH application ID:** 10903013
- **Project number:** 1F32AI183748-01
- **Recipient organization:** CARNEGIE INSTITUTION OF WASHINGTON, D.C.
- **Principal Investigator:** Robert John Scheffler
- **Activity code:** F32 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $76,756
- **Award type:** 1
- **Project period:** 2024-09-01 → 2025-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10903013

## Citation

> US National Institutes of Health, RePORTER application 10903013, Coordinated growth in microbial communities and implications for antibiotic sensitivities (1F32AI183748-01). Retrieved via AI Analytics 2026-05-25 from https://api.ai-analytics.org/grant/nih/10903013. Licensed CC0.

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