Middle ear infections, which affect more than 85 % of kids under the age of 3, could be triggered with a viral infection within the nose instead of solely with a bacterial infection, according to researchers at Wake Forest Baptist Medical Center.
By simultaneously infecting the nose having a flu virus and a bacterium that’s one of the main causes of ear infections in children, they discovered that influenza virus inflamed the nasal tissue and significantly increased both the number of bacteria as well as their propensity to travel through the Eustachian tube and infect the center ear.
The study is published in the current online issue of the American Society for Microbiology’s journal Infection and Immunity.
“Every individual has bacteria within the nose that most of the time doesn’t create problems,” said the study’s lead author, W. Edward Swords, Ph.D., professor of microbiology and immunology at Wake Forest Baptist. “However, under certain conditions those bacteria can migrate towards the middle ear and cause an ear infection, so we have a better knowledge of how and why that happens.”
The bacterium used in the animal study, Streptococcus pneumoniae, may exist in the noses of children in 2 phases, one relatively invasive and the other relatively benign. The greater invasive phase is more frequently based in the infected ears of kids. However, the study established that the flu virus promoted bacterial growth and ear infection no matter which phase from the bacterium was contained in the nose.
“These findings suggest that a flu infection modifies the response from the defense mechanisms for this particular bacterium, enabling even the type which has previously been considered benign to infect the center ear,” Swords said.
Work in Swords’ laboratory is sponsored by NIH Institute of Deafness along with other Communication Diseases grant R01 DC10051 and? AstraZeneca.
Co-authors of the study are John T. Wren, B.S., Lance A. Blevins, B.S., Bing Pang, Ph.D., Lauren B. King, Ph.D., Antonia C. Perez, Ph.D., Kyle A. Murrah, Ph.D., Jennifer L. Reimche, B.S., and Martha A. Alexander-Miller, Ph.D., all Wake Forest Baptist.
