Despite maintaining the highest levels of hygiene during cosmetic surgery, customers experience unpleasant side effects in the form of tender subcutaneous lumps that are difficult to treat.
In isolated cases these complications also lead to lesions that simply will not heal.
Injections of fillers were previously reserved exclusively for trauma treatment - when rebuilding a face disfigured in a traffic accident, for example.
However, the jelly-like substances are increasingly being used in beauty treatments with the intention of making lips swell up and to erase the effects of ageing from the skin.
Morten Alhede, a postdoc at the Department of International Health, Immunology and Microbiology, University of Copenhagen, said previously, most experts believed that the side effects were caused by an auto-immune or allergic reaction to the gel injected.
He said that research involving tissue from patients and mouse models has now shown that the disfiguring lesions are actually due to bacteria injected in connection with the cosmetic procedure.
Associate Professor Thomas Bjarnsholt from the Department of International Health, Immunology and Microbiology, said that the problem will become very serious when the treatment becomes so widespread that people are able to walk in off the street to have their wrinkles smoothed out.
The biofilm that can develop in the wake of a filler treatment is resistant to antibiotics.
The results have just been published in the journal Pathogens and Disease.