MRSA Colonization. MRSA Colonization is the term used to describe those who have drug resistant staph aureus bacteria on or in their bodies but have not yet become ill through the infection of a wound or other area of tissue.The bacteria is often found in the nose, groin or underarm areas.RSA Colonization. MRSA Colonization is the term used to describe those who have drug resistant staph aureus bacteria on or in their bodies but have not yet become ill through the infection of a wound or other area of tissue.