Bone and joint infections are most often caused by a type of bacteria known as Staphylococcus (or Staph for short). Staph infections are usually treated with antibiotics, often for several weeks, depending on the exact type of infection. Some Staph bacteria can become resistant to these antibiotics, which means that they can no longer be killed by that antibiotic. Also, the commonly used antibiotics do not kill only Staph bacteria but they kill other bacteria, including the beneficial bacteria normally present in your body.