My Husband Had Mersa In His Knee Last Year, He

My husband had Mersa in his knee last year, he was on strong antibotics for quite a while and also had a wound vac etc. his knee is still swollen where the MERSA was and opens up if he kneels or does anything on his knee. Am concerned about the MERSA does it stay in your body forever and does he need to get a dr to look at his knee again? Thanks MJ