Study Explores Disease-Causing Mechanisms of Pneumococcus
Published September 8, 2014 This content is archived.
Anthony A. Campagnari, PhD
Story by Suzanne Kashuba
Anthony A. Campagnari, PhD, professor of microbiology/immunology and medicine, will use novel biofilm and animal models to study key disease mechanisms and infection-causing phenotypes of a prominent middle ear pathogen.
He and his colleagues aim to reveal exactly how the Streptococcus pneumoniae bacterium transitions from colonization in the human nasopharynx to otitis media.
Toward New Antimicrobial Treatments
Campagnari received a five-year, $1.7 million grant from the National Institute on Deafness and Other Communication Disorders for the study.
“Our results will not only broaden our knowledge of pneumococcal pathogenesis; they will provide a better understanding of the mechanisms utilized by otopathogens in polymicrobial biofilms to cause disease,” Campagnari says.
“These data could lead to the development of novel antimicrobial treatments designed to eradicate biofilms in the middle ears of children, thus preventing recurrent otitis media.”
The S. pneumoniae bacterium is a primary cause of numerous infections, including otitis media, which can lead to hearing loss and impair language and cognitive development in children.
Novel Biofilm Models, Environmental Alterations
The research team seeks to learn how biofilm-associated pneumococci in the upper part of the throat are released to disseminate and induce middle ear disease.
To study the process, Campagnari and his team will employ novel epithelial cell-based biofilm models using S. pneumoniae alone as well as in polymicrobial biofilms involving the other major otopathogens — Moraxella catarrhalis and Haemophilus influenzae — and animal models of colonization and infection.
New laboratory and animal experiments will involve changing the normal nasopharyngeal biofilm environment to create conditions associated with an increased chance of middle ear infection.
These alterations will include physiological assaults involving:
- increased temperature or fever
- depletion of nutrients and adenosine triphosphate (ATP) or energy-storing molecules
- virus infection, a common disease trigger highly associated with pneumococcal otitis media
Building on Prior Discoveries
The researchers will build on prior studies that discovered pneumococci, as well as the other otopathogens, colonize the nasopharynx as biofilms. Through experiments in the laboratory and with animals, the UB team developed methodologies to study the signals responsible for the transition from bacterial colonization to middle ear disease.
They learned this transition is associated with biofilm formation as well as with certain conditions in the nasopharynx.
“Moreover, we have discovered that perturbation of the environment in the nasopharynx releases bacteria from the biofilm and these organisms readily disseminate to the middle ear, causing more severe disease than either biofilm-associated bacteria or bacteria cultured in the lab,” Campagnari notes.
“As a result, we have a unique transciptome profile that has identified several molecules involved in bacterial release, dissemination and induction of otitis media.”
The project, “Pneumococcal Transition from Nasopharyngeal Biofilm Carriage to Otitis Media,” also involves the following researchers:
- Nicole Luke-Marshall, PhD, research assistant professor of microbiology and immunology
- Anders P. Hakansson, PhD, former UB assistant professor of microbiology and immunology