Selective pressure is thought to play an important role, and use of beta-lactam antibiotics has been implicated as a risk factor for infection and colonization.
Klona MRSA, najtesneje povezana z izbruhi v javnosti, sta USA400 (sev MW2, rod ST1) in USA300, ki pogosto vsebuje" Panton-Valentine Leukocidin" (PVL) geni in se pogosteje povezuje z okužbami kože in mehkih tkiv.