Not all kinds of arthritis are caused by infection. A certain form of arthritis called infectious arthritis or septic arthritis is caused by microbial infection. The infection can be caused by bacteria, virus or fungi. Bacteria like Staphylococcus aureus, Streptococcus pneumoniae, Streptococcus viridans, group B streptococci, Neisseria gonorrhoeae are common causes of septic arthritis.

 Mycobacterium and fungi like Mycobacterium tuberculosis, Candida albicans etc can also cause this condition. Infection in any part of the body like respiratory tract infections, gastrointestinal infections, urinary tract infections etc can cause septic arthritis. It happens when the infectious agent travels from the site of infection to the joints and causes inflammation in the joints. Deep wounds at the joint area or previous surgery in the joints may also cause septic arthritis. It is characterized by pain, redness and swelling in the joints, fever, chills and so on. Blood tests, synovial fluid culture and X-ray will help diagnose this condition and identify the causative organism.

Treatment involves use of antibiotics to counter the microorganism causing the condition. Sometimes, the joint fluid will have to be drained to reduce microbial population. This is done repeatedly till the point when no bacteria is found in the fluid. Pain killers and anti inflammatory agents may also be prescribed.