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| X-ray image of an orthopedic implant on a femur taken a year and a half after surgery. Photo by Booyabazooka/Wikimedia Commons |
By Allen Cone, UPI
Researchers have discovered bacteria and fungi can grow on implants that have been inserted into patients, including for hip or knee replacement or broken bones.
[post_ads]Despite no signs of infection, researchers at University of Copenhagen in Denmark found devices, including screws, pacemakers and related material contained bacteria and fungi, but none were pathogens such as staphylococcus. The findings were published Monday in the scientific journal APMIS.
"This opens up a brand new field and understanding of the interplay between the body and bacteria and microbiomes," researchers from the school's Faculty of Health and Medical Sciences said in a press release. "We have always believed implants to be completely sterile. It is easy to imagine, though, that when you insert a foreign body into the body, you create a new niche, a new habitat for bacteria."'
Study author Thomas Bjarnsholt, a professor in the Department of Immunology and Microbiology, said the researchers need to determine whether the bacteria and fungi are beneficial, precursors to infection or are insignificant. Though Bjarnsholt said they appear to remain there for a long time, they probably are there without affecting patients.
The researchers examined 106 implants and the surrounding tissue from different patient groups, finding that more than 70 percent had been colonized by bacteria, fungi or both.
The samples came from patients with aseptic loosening, craniofacial implants, healed fractures or had a disease that resulted in needing an implant.
Fungi was the same across types of implant, but a significant majority of screws were found to be colonized by bacteria -- with the exception of those used on knees.
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Also conducted were 39 controls to determine that the implants had not simply been contaminated in the process of collecting samples or the subsequent analysis. All the controls were negative, suggesting the fungi and bacteria collect inside the body over time, Bjarnsholt said.
In 2013, researchers at the University of Massachusetts Medical School found patients with implanted medical devices like pacemakers or prosthetic hips or knees are at risk of infection if the implant carries a fungus into the body.
