New research suggests that some patients develop a potentially deadly blood infection from their implanted cardiac devices because bacterial cells in their bodies have gene mutations that allow them to stick to the devices.
The scientific principles governing the formation of bacterial biofilms on cardiac devices are strongly linked with those of biofilm formation on mineral surfaces, hence the connection with geobiology.
Geoscientists were the major contributors to the finding.
Proceedings of the National Academy of Sciences published the study results online this week.
“Geobiologists, key to these results, use atomic force microscopy to study the forces with which bacteria adhere to mineral surfaces,” said Enriqueta Barrera, program director in the National Science Foundation’s Division of Earth Sciences, which funded the research.
“These scientists have adapted this approach, along with molecular dynamics simulations, to gain a better understanding of the strength with which the proteins of infectious bacteria adhere to cardiac implants,” said Barrera. “Such results might have implications for the development of medication to treat this type of infection.”
Patients with implants can develop infections because of a biofilm of persistent bacteria on the surfaces of their devices.
A biofilm is a community of bacterial cells that lives on the surface of a solid substrate. Biofilms are the most common mode of life for all bacteria, whether they reside in the environment or in the human body.
The scientific principles governing the formation of bacterial biofilms on cardiac devices are strongly linked with those of biofilm formation on mineral surfaces, hence the connection with geobiology.
Scientists found that some strains of the bacteria, Staphylococcus aureus, have just a few genetic variants in the proteins on their surfaces that make them more likely to form these biofilms.
The research seeks to get to the heart of a medical paradox: devices such as pacemakers, defibrillators and prosthetic cardiac valves save lives, but they cause infections in about 4 percent of the estimated 1 million patients receiving implants each year in the United States.
Because biofilms resist antibiotics, the only treatment is surgery to remove the contaminated device and implant a new one. This adds up to thousands of surgeries and more than $1 billion in health care costs every year.
A team led by scientists at Ohio State University and Duke University Medical Center used atomic force microscopy and powerful computer simulations to determine how Staph bacteria bond to the devices in the process of forming these biofilms.
The findings offer clues about potential techniques that could be employed to prevent infections in patients who need these devices to stay alive.
“We’re probing the initial step to that biofilm formation,” said Steven Lower, scientist at Ohio State and lead author of the paper reporting the study’s results.
“Can you shut that down somehow? If that bacterium never sticks, there’s no biofilm. It’s that simple. But it’s not quite that simple in practice.”
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Source: National Science Foundation
published: October 28, 2011 in: Cardio, General Surgery, Gynaecology/Obstetrics, Journals, Neuro, News, Ophthalmics, Oral/Maxillofacial, Orthopaedics, Spine, Technology