Surface proteins play many critical roles in MRSA
pathogenesis. They have many functions including
cell wall metabolism, immune evasion, bacterial
aggregation and biofilm formation (67). Most surface
genes are located on the core genome, so the virulence
of MRSA may not be directly related to surface
proteins. SasX on MGE promotes MRSA colonization
by boosting bacterial aggregation which shares similar
characteristics compared to aggregation caused by
surface proteins