what is mrsa illness
In this article. Methicillin-resistant Staphylococcus aureus (MRSA) is a bacterium that causes infections in different parts of the body. It's tougher to treat than most strains of staphylococcus aureus -- or staph -- because it's resistant to some commonly used antibiotics.The symptoms of MRSA depend on where you're infected. Most often, it causes mild infections on the skin, like sores or boils.t's tougher to treat than most strains of staphylococcus aureus -- or staph -- because it's resistant to some commonly used antibiotics. The symptoms of MRSA depend on where you're infected. Most often, it causes mild infections on the skin, like sores or boils.