What bad effects can occur if a newborn baby gets colonized with mrsa?

May become ill: Most of us carry staphylococci in our bodies somewhere, often on the skin and mucous membranes of the upper respiratory tract. This includes mrsa. You may be able to minimize the risk of its producing infection at a later date by attempting to eliminate it with Mupirocin nasal application and washing with Chlorhexidine containing soap, but ask your pediatrician about this.

Quite varied: Colonization can result in a wide spectrum of effects, sometimes very mild or unnoticeable.