Abstract All micro-organisms can cause joint and bone disease, but bacterial arthritis is more common and the most potentially dangerous and destructive. Micro-organisms can cause disease by active infection, reaction to the organism and inflammation induced by auto activation of the immune system. Infection may arise due to a contiguous focus of infection or its haematogenous spread. Bacterial cell surface components are important in the pathogenesis of septic arthritis and trigger a cascade of events that lead to the generation of inflammation. The principles of management are prompt diagnosis, early and prolonged therapy with appropriate antibiotics, together with joint or abscess drainage. Mortality is dependent on the presence of co-morbid conditions for instance age and co-existent diseases such as rheumatoid arthritis. Despite our increasing understanding of the sophisticated process of microbial infection, there has not been a significant improvement in prognosis over the past decades.