The outlook for septic arthritis depends on the precise microbe causing the infection, the duration of the infection, and the underlying overall health of the individual infected. Some types of microorganisms are more aggressive and difficult to treat than others. The longer the infection is present, the more opportunity for damage to affect the joint. People whose immune systems are not functioning optimally are also at risk for more joint damage. Moreover, if septic arthritis leads to infection in other parts of the body, other organs can be affected.