Direct Demonstration of Viable Staphylococcus aureus Biofilms in an Infected Total Joint Arthroplasty

Abstract

Infection following total joint arthroplasty is difficult to diagnose and treat; a nascent body of evidence from studies of prosthetic joint infections suggests that biofilm bacteria are the underlying cause. We describe the case of a patient who had chronic recurring symptoms of infection that persisted for years following total elbow arthroplasty despite numerous medical and surgical interventions. Confocal microscopy performed on fluid, tissue, and cement at the final surgical revision demonstrated viable bacteria in biofilm aggregates. Reverse transcriptase-polymerase chain reaction analysis confirmed the presence of metabolically active Staphylococcus aureus. These observations comprise compelling evidence that viable biofilm bacteria play an important role in refractory infection following joint arthroplasty.Chronic infection following joint replacement is increasingly thought to result from the presence of bacterial biofilm communities attached to the implant. Biofilm bacteria are vastly more resistant to conventional antibiotic therapy than are their single planktonic counterparts (unattached solitary bacteria living freely) and are typically difficult to culture by conventional microbiological methods. The biofilm paradigm can explain contradictory signs and symptoms that suggest infection but are often associated with negative cultures. Moreover, biofilm infections are difficult to detect by simple Gram stain and culture techniques but can persist as a nidus of infection from which recurrent acute exacerbations may arise through episodic planktonic “showering”.