Featured Research

from universities, journals, and other organizations

New way to prevent recurrent ear infections?

Date:
October 30, 2012
Source:
Nationwide Children's Hospital
Summary:
Eliminating bacteria’s DNA and boosting antimicrobial proteins that already exist may help prevent middle ear infections from reoccurring. These are the findings from a new study that examined how an immune defense protein common in the middle ear interacts with a structure meant to protect a colony of bacteria.

Eliminating bacteria's DNA and boosting antimicrobial proteins that already exist may help prevent middle ear infections from reoccurring. These are the findings from a Nationwide Children's Hospital study that examined how an immune defense protein common in the middle ear interacts with a structure meant to protect a colony of bacteria.

The bacterium nontypeable Haemophilus influenzae (NTHI) causes a wide range of diseases of both the lower and upper airways, including middle ear infection. NTHI, like most other bacteria, can form a biofilm, a robust community of bacteria that allows the bacteria to evade the host's immune system and protects the bacteria from antibiotics and other therapies designed to kill them.

Human beta-defensin-3 is an antimicrobial defense protein expressed in the middle ear of humans and other mammals that kills both Gram-positive and Gram-negative bacteria. Previous research has shown that if expression of beta-defensin is disrupted, the host's ability to control the bacteria in the upper airway is altered and infection worsens.

Investigators in The Research Institute at Nationwide Children's Hospital hypothesized that human beta-defensin-3 might lose its power to kill NTHI if it got caught up within the extracellular DNA that makes up a biofilm's outer layer, thus preventing its contact with bacteria within the biofilm.

"Antimicrobial host defense proteins, like human beta-defensin-3, have been shown to bind to non-host DNA," says Lauren O. Bakaletz, PhD director of the Center for Microbial Pathogenesis "This interaction has an impact on the defense protein's ability to function."

Upon examining their animal model of middle ear infection, Dr. Bakaletz' team found that bacterial DNA and the animal's defense peptides were detected together in biofilms that developed during infection. Also, the defense peptide was predominantly co-localized with the biofilm's extracellular DNA.

When the team exposed the bacteria that cause ear infections to a concentration of human-beta defensin-3 that is typically detected in the a middle ear of a child with active infection, the peptide was able to kill 100 percent of the NTHI, but the killing stopped when extracellular DNA was introduced to the reaction.

"These data support the conclusion that the killing activity of the antimicrobial defense protein was decreased in an NTHI-induced biofilm due to its interaction with eDNA," says Dr. Bakaletz, who is the lead study author and professor of Pediatrics and Otolaryngology at The Ohio State University College of Medicine.

When they removed extracellular DNA from the biofilm, the killing activity of the defense peptide was rescued.

"The ability to restore antimicrobial defense protein activity is encouraging, since biofilms are resistant to most treatments, including traditional antibiotics," says Dr. Bakaletz.

Dr. Bakaletz says this study provides evidence for a new treatment regimen to target biofilms formed by NTHI during middle ear infection. One approach would be to deliver a therapeutic agent that can disrupt bacterial DNA, in conjunction with human beta-defensin-3 to the middle ear of a child with chronic, recurrent infection. Physicians could follow the same pathway used to target the middle ear during ear tube surgery, a common treatment for chronic ear infections.

"This approach would likely bolster the ability of the innate immune system to manage NTHI-induced biofilms, avoiding the need for antibiotics or empowering the use of antibiotics we already have in our arsenal," says Dr. Bakaletz. "Doing so could help diminish the recurrent nature of middle ear infection."


Story Source:

The above story is based on materials provided by Nationwide Children's Hospital. Note: Materials may be edited for content and length.


Journal Reference:

  1. Eric A. Jones, Glen McGillivary, Lauren O. Bakaletz. Extracellular DNA within a Nontypeable Haemophilus influenzae-Induced Biofilm Binds Human Beta Defensin-3 and Reduces Its Antimicrobial Activity. Journal of Innate Immunity, 2012; DOI: 10.1159/000339961

Cite This Page:

Nationwide Children's Hospital. "New way to prevent recurrent ear infections?." ScienceDaily. ScienceDaily, 30 October 2012. <www.sciencedaily.com/releases/2012/10/121030101340.htm>.
Nationwide Children's Hospital. (2012, October 30). New way to prevent recurrent ear infections?. ScienceDaily. Retrieved September 17, 2014 from www.sciencedaily.com/releases/2012/10/121030101340.htm
Nationwide Children's Hospital. "New way to prevent recurrent ear infections?." ScienceDaily. www.sciencedaily.com/releases/2012/10/121030101340.htm (accessed September 17, 2014).

Share This



More Plants & Animals News

Wednesday, September 17, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Some Tobacco Farmers Thrive Amid Challenges

Some Tobacco Farmers Thrive Amid Challenges

AP (Sep. 16, 2014) The South's tobacco country is surviving, and even thriving in some cases, as demand overseas keeps growers in the fields of one of America's oldest cash crops. (Sept. 16) Video provided by AP
Powered by NewsLook.com
Scientists Given Rare Glimpse of 350-Kilo Colossal Squid

Scientists Given Rare Glimpse of 350-Kilo Colossal Squid

AFP (Sep. 16, 2014) Scientists say a female colossal squid weighing an estimated 350 kilograms (770 lbs) and thought to be only the second intact specimen ever found was carrying eggs when discovered in the Antarctic. Duration: 00:47 Video provided by AFP
Powered by NewsLook.com
Raw: Scientists Examine Colossal Squid

Raw: Scientists Examine Colossal Squid

AP (Sep. 16, 2014) Squid experts in New Zealand thawed and examined an unusual catch on Tuesday: a colossal squid. It was captured in Antarctica's remote Ross Sea in December last year and has been frozen for eight months. (Sept. 16) Video provided by AP
Powered by NewsLook.com
Ivorians Abandon Monkey Pets in Fear Over Ebola Virus

Ivorians Abandon Monkey Pets in Fear Over Ebola Virus

AFP (Sep. 16, 2014) Since the arrival of Ebola in Ivory Coast, Ivorians have been abandoning their pets, particularly monkeys, in the fear that they may transmit the virus. Duration: 00:47 Video provided by AFP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

    Technology News



    Save/Print:
    Share:

    Free Subscriptions


    Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

    Get Social & Mobile


    Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

    Have Feedback?


    Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
    Mobile: iPhone Android Web
    Follow: Facebook Twitter Google+
    Subscribe: RSS Feeds Email Newsletters
    Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins