Human monoclonal antibodies against <i>Staphylococcus aureus</i> surface antigens recognize in vitro and in vivo biofilm.

Abstract

Implant-associated <i>Staphylococcus aureus</i> infections are difficult to treat because of biofilm formation. Bacteria in a biofilm are often insensitive to antibiotics and host immunity. Monoclonal antibodies (mAbs) could provide an alternative approach to improve the diagnosis and potential treatment of biofilm-related infections. Here, we show that mAbs targeting common surface components of <i>S. aureus</i> can recognize clinically relevant biofilm types. The mAbs were also shown to bind a collection of clinical isolates derived from different biofilm-associated infections (endocarditis, prosthetic joint, catheter). We identify two groups of antibodies: one group that uniquely binds <i>S. aureus</i> in biofilm state and one that recognizes <i>S. aureus</i> in both biofilm and planktonic state. Furthermore, we show that a mAb recognizing wall teichoic acid (clone 4497) specifically localizes to a subcutaneously implanted pre-colonized catheter in mice. In conclusion, we demonstrate the capacity of several human mAbs to detect <i>S. aureus</i> biofilms in vitro and in vivo.