Scanning electron microscope image of Acinetobacter baumannii bacteria (CDC.gov)
11 November 2015. Washington State University engineers and medical researchers developed an electronic stimulation patch that in lab tests kills nearly all drug-resistant bacteria it contacts. The team from the lab of bioengineering professor Haluk Beyenal published its proof-of-concept findings in a recent issue of the journal Scientific Reports.
Beyenal’s lab in Pullman, Washington studies electrochemical properties of biofilms, communities of microbes that connect and expand through a matrix of organic matter. These microbe colonies stick tightly to surfaces, including the skin, making them difficult to treat, because of their persistence and ability to resist conventional antibiotics. When biofilms cause skin infections, the bacteria are further protected by the outermost layer of the film.
In the study, the Washington State team focused on biofilms of Acinetobacter baumannii bacteria. Acinetobacter is a notorious bacteria, associated with infections in health care facilities, especially those that treat very ill patients, such as intensive care units. Besides striking highly vulnerable populations, Acinetobacter is also now resistant to many conventional antibiotics. Acinetobacter baumannii make up about 80 percent of all Acinetobacter infections.
The authors note that electronic stimulation has been tried for more than a century to treat wound infections, but with mixed results. Electronic treatments were largely ignored after early advances in antibiotics and little understanding developed of the ways electronic stimulation worked to control bacteria. Beyenal and colleagues, however, studied these mechanisms. “We have been doing fundamental research on this for many years,” says Beyenal in a university statement, “and finally, we are able to transfer it to technology.”
In previous work, the researchers found electronic stimulation produced hydrogen peroxide, a common and effective disinfectant, on the surface of electrodes emitting the current. The team fabricated a circular scaffold patch with conductive, commercially-available carbon fabric. Electrodes were built into the scaffold, attached with a silicone rubber sealant that also left a thin open layer under the device for hydrogen peroxide to form.
The researchers first tested the device on Acinetobacter bacteria in lab cultures. The team applied the patch to Acinetobacter baumannii biofilms and ran a low, constant electric current through device. After 24 hours, the team reports a reduction of 99.99 percent of bacteria in the culture, with about an 80 percent reduction of the biofilm surface area.
The researchers then tested the device on samples of pig tissue infected with Acinetobacter baumannii biofilms. Results show after 24 hours, the patch reduced the amount of bacteria by 99.9 percent, with no observable damage to the underlying tissue.
The development team applied for a patent on the technology, and plans to test the device with a wider range of bacteria.
Read more:
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- Anti-Infection Compound Devised for Dental, Wound Care
- Alliance Building Platform Against Drug-Resistant Infections
- Hand-Held DNA Sequencer IDs Bacteria, Viruses
- Computer Model Predicts Bacteria Mutations, Aids Drug Design
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