Biofilm-Glycocalyx in Orthopaedics
Introduction: In orthopaedics, biofilm-glycocalyx plays a pivotal role in the pathogenesis, persistence, and treatment challenges of implant-associated infections and chronic osteomyelitis. A biofilm is a complex microbial community encased within a self-produced extracellular polymeric substance (EPS), predominantly composed of polysaccharides, proteins, lipids, and extracellular DNA known collectively as the glycocalyx. This sessile bacterial lifestyle confers resistance to host immune mechanisms and antibiotic therapies, making infections difficult to eradicate. Understanding the microbiology, pathogenesis, clinical implications, diagnosis, and management of biofilm-glycocalyx is essential for postgraduate orthopaedic surgeons to effectively treat implant-related and chronic bone infections.
1. Definition and Orientation
Biofilm is defined as a structured consortium of microbial cells attached irreversibly to a surface and embedded within a self-produced extracellular matrix called the glycocalyx. This polymeric matrix comprises polysaccharides, proteins, lipids, and extracellular DNA (eDNA), which protect the bacteria from external insults.
In orthopaedics, biofilms adhere primarily to foreign bodies (implants such as joint prostheses, plates, nails, and external fixators), necrotic bone, and chronically infected tissues. Because bacteria within biofilms manifest altered phenotypes, including reduced metabolic activity and gene expression changes, they exhibit marked tolerance to antibiotics and host immune responses compared to their planktonic (free-floating) counterparts.