Breast implant microbiome profile correlates with foreign body response severity.

Biomedical implants significantly enhance quality of life for millions of individuals worldwide. However, maintaining long-term implant function remains challenging, and it is often due to a severe foreign body response, characterized by fibrosis and functional impairment, clinically referred to as capsular contracture for breast implants. Colonization of implant surfaces by low-virulent bacteria has been proposed as a potential driver of severe foreign body response, but evidence from large-scale human studies has been lacking. We found that the implant microbiome composition is significantly associated with the foreign body response severity based on an extensive characterization of the breast implant microbiome using 16S rRNA gene amplicon sequencing. We analyzed 339 explanted breast implants from 206 patients undergoing revisional surgery without any symptoms of a clinical infection. We detected a diverse community of bacteria on the implants and demonstrated that an increased relative abundance of Staphylococcus was associated with a severe foreign body response. This pattern was supported by a within-patient analysis of 20 individuals with unilateral severe versus contralateral mild foreign body response. These findings suggest that the implant microbiome plays a role in the development of a severe foreign body response and may guide strategies to improve implant biocompatibility. STATEMENT OF SIGNIFICANCE: This study identified a diverse microbiome on breast implants from patients without any symptoms of infection and demonstrated a clear association between microbiome composition and the severity of the foreign body response (FBR), a significant complication affecting implant function. Notably, implants with severe FBR showed lower microbial diversity and higher relative abundance of Staphylococcus compared to those with mild FBR. Additionally, a paired analysis within patients with severe FBR in one breast and mild FBR in the contralateral breast further supported higher relative Staphylococcus abundance on the severe FBR implant. These findings provide insights into microbial factors influencing implant biocompatibility, which may guide strategies to improve implant biocompatibility and reduce complications for patients.