Detection of Bacteria by Fluorescence in Situ Hybridization in Culture-Negative Soft Tissue Filler Lesions

BACKGROUND Adverse reactions to polyacrylamide gel occur as swellings or nodules, and controversy exists whether these are due to bacterial infection or an autoimmune reaction to the filler. OBJECTIVES Biopsies from culture-negative long-lasting nodules after injection with different types of polyacrylamide gel were examined with a combination of Gram stain and fluorescence in situ hybridization. RESULTS Bacteria were detected in biopsies from seven of eight patients. They inhabited gel and intervening tissue and tended to lie in aggregates. CONCLUSION This study supports the assumption that infection with bacteria in aggregates causes culture-negative late adverse reactions to polyacrylamide gel, suggesting a biofilm environment.