# Bacterial factors and host response in chronic otitis media

> **NIH NIH R21** · UNIVERSITY OF GEORGIA · 2020 · $226,500

## Abstract

Abstract
Advances in our understanding of otitis media is slowed by limitations of experimental systems
that, for example, inject large inocula of human pathogens into the middle ears of rodents. Such
approaches bypass the progression from natural colonization to disease, and the pathogens fail
to persist in the middle ears as chronic infections, the period when complications of the disease
usually begin to set in. We recently observed that the gram-negative bacteria Bordetella
bronchiseptica and Bordetella pseudohinzii are very efficient colonizers of the middle ears of mice.
Despite being phylogenetically related, B. bronchiseptica efficiently induces acute inflammation
but fails to establish a chronic infection. B. pseudohinzii also induces an early acute inflammatory
response but persists indefinitely as a chronic infection in the middle ears, inducing hearing loss
and pathology mimicking chronic otitis media in humans. Here, we will use these two contrasting
pathogen models of otitis media to uncover the virulence factors of oto-pathogens that lead to
chronic infection and uncover host immune mechanisms that determine acute versus chronic
infections. We will make genome comparisons to highlight their genetic differences and then focus
on the stage specific transcriptional profiles of these genes as B. pseudohinzii and B.
bronchiseptica progress through the early, acute and chronic stages of middle ear infection in
mice. From this list of uniquely expressed genes, we will prioritize and select putative genes
implicated in the different stages of infection. We will then delete these to assess the roles of each
in pathogenesis and persistence. We also propose to make preliminary investigations of the
adaptive immune system and to establish the difference in the host response when confronted
with acute and chronic middle ear pathogens.

## Key facts

- **NIH application ID:** 9998548
- **Project number:** 1R21DC018496-01A1
- **Recipient organization:** UNIVERSITY OF GEORGIA
- **Principal Investigator:** Eric T Harvill
- **Activity code:** R21 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $226,500
- **Award type:** 1
- **Project period:** 2020-04-01 → 2022-03-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9998548

## Citation

> US National Institutes of Health, RePORTER application 9998548, Bacterial factors and host response in chronic otitis media (1R21DC018496-01A1). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/9998548. Licensed CC0.

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