Are bacterial growth and/or chemotaxis increased by filler injections? Implications for the pathogenesis and treatment of filler-related granulomas.

BACKGROUND As microbial agents have been associated with late adverse effects related to fillers antibiotic treatment has been envisaged. OBJECTIVE To determine whether biomaterials favor bacterial growth and/or attract bacteria. METHODS Hyaluronic acid, semi-permanent fillers, such as calcium hydroxylapatite, and permanent fillers, such as polyalkylimide/polyacrylamide, were used. Experiments were performed with Escherichia coli, strain HVH-U47. Bacteria were transferred to Sven-Gard agar to test mobility. Striae of this bacterial strain with a MacFarland 1 turbulence pattern were seeded from a spot of inoculated biomaterial using Müller-Hinton medium. The chemoattractive properties of the biomaterials were analyzed 10 days after inoculation. Bacterial growth over the biomaterial and in-depth growth were assessed as well. RESULTS Semi-permanent fillers did not stimulate bacterial growth but they allowed bacterial colonization over the filler. Permanent acrylic compounds neither presented chemoattractant properties nor showed bacterial growth over the biomaterial. Similar results were obtained when performing in-depth cultures. CONCLUSIONS Permanent and semi-permanent fillers did not facilitate bacterial growth when flagellated E. coli HVH-U47 was used. Our results do not argue in favor of antibiotics as the mainstay of therapy in late granulomas related to permanent fillers. In the case of resorbable/semi-permanent fillers, more studies are needed before recommending antibiotic therapy.