Pathophysiology of a MRSA Infection

Methicillin-resistant Staphylococcus aureus (MRSA) is a species of bacteria that often causes infections that are difficult to treat. MRSA infections occur primarily on the skin, but they can also occur in the lungs (pneumonia) or the blood (sepsis).

MRSA

• MRSA bacteria are resistant to most antibiotics normally used to treat Staphylococcal infections. This makes them difficult to treat since the antibiotics that do work are very strong and have some side-effects. As a result, MRSA is a serious infection, particularly to those in a weakened state.

Colonization

• MRSA are normal bacteria (flora) of the skin and nostrils of many people. The bacteria colonize those body parts and crowd out other normal flora. Symptoms of MRSA on the skin begin with infection.

Infection

• Infection occurs when the the antibiotic-resistant bacteria begin to cause damage to or colonize a normally sterile body site. For example, blood is sterile under normal conditions. As the bacteria multiply, they produce toxins that damage cells.

Damage

• Cell and tissue damage occurs from the toxins produced as the bacteria grow and from the body's immune response against the infection. The toxins and immune system byproducts destroy the cell walls of cells they come in contact with.

Fever

• Besides direct cell damage, MRSA infections, like other infections, cause fever. Fever results as a side-effect of the immune response. If not treated, high fevers may cause brain damage and other complications.