Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Study Suggests New Way to Prevent Recurrent Ear Infections

31.10.2012
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.”

Jones EA, McGillivary G, Bakaletz LO. Extracellular DNA within a Nontypeable Haemophilus influenzae -Induced Biofilm Binds Human Beta Defensin-3 and Reduces Its Antimicrobial Activity. J Innate Immun. 2012 Aug 22. [Epub ahead of print]

Erin Pope | Newswise Science News
Further information:
http://www.nationwidechildrens.org

More articles from Health and Medicine:

nachricht 'Living bandages': NUST MISIS scientists develop biocompatible anti-burn nanofibers
16.02.2018 | National University of Science and Technology MISIS

nachricht New process allows tailor-made malaria research
16.02.2018 | Eberhard Karls Universität Tübingen

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: In best circles: First integrated circuit from self-assembled polymer

For the first time, a team of researchers at the Max-Planck Institute (MPI) for Polymer Research in Mainz, Germany, has succeeded in making an integrated circuit (IC) from just a monolayer of a semiconducting polymer via a bottom-up, self-assembly approach.

In the self-assembly process, the semiconducting polymer arranges itself into an ordered monolayer in a transistor. The transistors are binary switches used...

Im Focus: Demonstration of a single molecule piezoelectric effect

Breakthrough provides a new concept of the design of molecular motors, sensors and electricity generators at nanoscale

Researchers from the Institute of Organic Chemistry and Biochemistry of the CAS (IOCB Prague), Institute of Physics of the CAS (IP CAS) and Palacký University...

Im Focus: Hybrid optics bring color imaging using ultrathin metalenses into focus

For photographers and scientists, lenses are lifesavers. They reflect and refract light, making possible the imaging systems that drive discovery through the microscope and preserve history through cameras.

But today's glass-based lenses are bulky and resist miniaturization. Next-generation technologies, such as ultrathin cameras or tiny microscopes, require...

Im Focus: Stem cell divisions in the adult brain seen for the first time

Scientists from the University of Zurich have succeeded for the first time in tracking individual stem cells and their neuronal progeny over months within the intact adult brain. This study sheds light on how new neurons are produced throughout life.

The generation of new nerve cells was once thought to taper off at the end of embryonic development. However, recent research has shown that the adult brain...

Im Focus: Interference as a new method for cooling quantum devices

Theoretical physicists propose to use negative interference to control heat flow in quantum devices. Study published in Physical Review Letters

Quantum computer parts are sensitive and need to be cooled to very low temperatures. Their tiny size makes them particularly susceptible to a temperature...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

2nd International Conference on High Temperature Shape Memory Alloys (HTSMAs)

15.02.2018 | Event News

Aachen DC Grid Summit 2018

13.02.2018 | Event News

How Global Climate Policy Can Learn from the Energy Transition

12.02.2018 | Event News

 
Latest News

'Lipid asymmetry' plays key role in activating immune cells

20.02.2018 | Life Sciences

MRI technique differentiates benign breast lesions from malignancies

20.02.2018 | Medical Engineering

Major discovery in controlling quantum states of single atoms

20.02.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>