A new University of Copenhagen study has found that surgical implants, such as screws inserted into the body, provide a habitat for bacteria and fungi to grow, contrary to the general belief that they are completely sterile.
The university’s Faculty of Health and Medical Sciences team analysed 106 implants, including knees and pacemakers, and the surrounding tissue from four different patient populations.
They observed that more than 70% of 78 implants had bacteria and/or fungal growth but none of the patients showed any signs of infection.
Bacterial colonisation was found to be common in case of screws, while the prevalence of fungi was similar in various types of implants. However, the researchers reported an absence of pathogenic microbes that can have a negative impact on patient’s health.
University of Copenhagen Immunology and Microbiology department assistant professor Tim Holm Jakobsen said: “It is important to stress that we have found no direct pathogens, which normally cause infection. Of course, if they had been present, we would also have found an infection.”
In order to ensure that the contamination is not occurring outside the body, the team examined 39 controls through the opening of a sterile implant in the laboratory, during surgery or removing it shortly post-implantation.
The researchers did not discover any bacteria or fungi in these controls and concluded that the colonisation occurs after the surgical implants are inserted into the body.
University of Copenhagen Immunology and Microbiology department professor Thomas Bjarnsholt said: “If our discovery of bacteria and fungi was simply a result of contamination, we would have reached the same results by inserting an implant in a patient and removing it again.
“But all the controls were negative. So it is something that develops inside the body over a period of time.”
The researchers plan to further investigate the effect of the identified bacteria and fungi on both the implant and the body, along with the mechanism behind their occurrence.