MRSA

My son was involved in an ATV accident in October and had massive head trauma. The right side bone flap was put back but his left side bone flap was left out. While he was in the hospital he contracted MRSA. The treated him for the MRSA and he's been fine ever since.  My son had surgery on July 13th to put in a artificial bone flap back on the left side and for 3 weeks he was healing great, no swelling, no fevers, ct scan showed nothing unusual. Then in less than 24 hours he had a 103.8 temp and his head started swelling.  We took him to the hospital and emergency surgery was preformed to remove the artificial piece and the doctors said he had an infection, they isolated it and now he's on antibiotics for the next 6 weeks. He once again has MRSA.  My question is was there anything the surgeons should or could have done to prevent this from happening, since they new he had MSRA before (Blood tests, preventive anibiotics before and after this surgery) and where do we go from here, because he will have to have this surgery again.  I appreciate your time. Thank you Michelle.