# Investigating the viable but not culturable (VBNC) state in P. gingivalis

> **NIH NIH R01** · UNIVERSITY OF FLORIDA · 2022 · $358,566

## Abstract

ABSTRACT
Bacterial species have evolved multiple mechanisms to survive ecological, nutritional and chemical stresses as
well as host cell defenses. Among these is to enter a viable but non-culturable (VBNC) state. As the name
indicates, bacteria in the VBNC state have lost the ability to grow on routine agar, but are in fact, alive, albeit in
a dormant (not spore) state. The ability of a bacterial species to enter the VBNC state and also resuscitation
from this state is now recognized to be an important or even required mechanism for the survival and
pathogenesis of several bacterial pathogens, especially those that are associated with chronic infections.
These proposed studies are designed to genetically and metabolically characterize the VBNC state and
resuscitation from the VBNC state of the oral pathogen, P. gingivalis. The goal, in addition to defining the P.
gingivalis gene expression and metabolism in the VBNC state is to also identify one or more biomarkers for the
VBNC state of P. gingivalis strain W83 (PgW83). In addition, knockouts of genes found to be specific for or
highly expressed during the VBNC and resuscitation states will be constructed. These mutants will then be
tested in both in vitro and in vivo models to determine the requirement for these genes, and thus the VBNC
state, in host cell invasion and virulence in an in vivo animal model. Our hypothesis is that the existence of
VBNC subpopulations with the ability to resuscitate allows P. gingivalis to survive those conditions of
intracellular stress that it encounters thus allowing P. gingivalis to exist and persist in a chronic state of
infection. We have designed in vitro and in vivo experiments to test this hypothesis. First, we propose to use
cellular and in vitro methods to establish the VBNC and resuscitation states of PgW83. Next, we will perform
RNAseq and metabolomics to identify possible biomarkers for VBNC and resuscitation states. Biomarker
mutants will be constructed and tested for their abilities to enter the VBNC and resuscitate within host cells.
Finally, we will treat mice with PgW83 wildtype and mutants defective in transitioning into and resuscitation
from the VBNC state to determine whether these states of P. gingivalis are necessary for chronic periodontitis.
These studies will provide new insights into the molecular events of P. gingivalis occurring during chronic
infections such as periodontitis and identify new protein targets for future therapies.

## Key facts

- **NIH application ID:** 10308015
- **Project number:** 5R01DE028656-03
- **Recipient organization:** UNIVERSITY OF FLORIDA
- **Principal Investigator:** Ann Progulske-Fox
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2022
- **Award amount:** $358,566
- **Award type:** 5
- **Project period:** 2019-12-13 → 2024-11-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10308015

## Citation

> US National Institutes of Health, RePORTER application 10308015, Investigating the viable but not culturable (VBNC) state in P. gingivalis (5R01DE028656-03). Retrieved via AI Analytics 2026-06-14 from https://api.ai-analytics.org/grant/nih/10308015. Licensed CC0.

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