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Understanding Methicillin-Resistant Staphylococcus aureus

Author(s): by Mary Pat Bolton, MA, RD, LD

Transmission of Methicillin-Resistant Staphylococcus aureus (MRSA)

Staph bacteria cause illness when they enter the body through skin wounds. Most MRSA infections occur through direct contact with people or surfaces that carry the germ. Approximately 25-30% of the human population is “colonized” with strains of S. aureus, meaning that the bacteria are present (usually on the skin or in the nose), but are not causing illness. Healthy people who carry S. aureus can pass the bacteria unintentionally to other people. Only about 1% of people who carry staph bacteria have methicillin-resistant strains.