Methicillin-resistant Staphylococcus aureus, or MRSA, can cause serious and potentially life-threatening infections. Though these types of infections occur more frequently on the skin, there are some common factors which can cause MRSA in the lungs. People who spend time in settings where MRSA is common, such as patients in hospitals, are more likely to become infected. Those with compromised immune systems or existing lung infections are also more susceptible. The use of a ventilator to help with breathing can also make people more likely to develop MRSA in their lungs.
Treatment in a health care setting is frequently the cause of a MRSA infection in the lungs. Hospitals and other treatment facilities house numerous patients, some of whom may be carrying the bacteria. Due to the close proximity of the patients, MRSA is frequently passed from one person to another. Those who require long-term care may be more likely to develop an infection, as their extended stay in a health care setting gives them a greater chance for exposure.
MRSA in the lungs is more likely to occur in people with a compromised immune system. Many people are exposed to MRSA on their skin or in their nasal passages but do not develop infections; certain diseases, however, such as HIV/AIDS, decrease the ability of sufferers to fight off infections from the bacteria. Some medical treatments, like chemotherapy, may also decrease immune function, making patients more susceptible. The fact that these types of people may also spend a significant amount of time in hospitals and other health care facilities where MRSA is common only contributes to the problem.
People whose lungs are already weakened by other diseases may tend to develop MRSA in the lungs as well. Those with diseases such as pneumonia, emphysema, or lung cancer already have weakened or damaged lungs. If the MRSA bacteria is present, the compromised tissue may be attacked and infected more easily than healthy lung tissue.
Being on a ventilator can lead to MRSA in the lungs. Patients who need assistance breathing while being treated for an injury or during an operation have a tube run down their trachea to their lungs. In some people, the presence of this tube seems to compromise their lungs, allowing infection to set in. Again, the fact that these people are usually in a hospital setting and therefore often exposed to MRSA only makes infection more likely.