MRSA Colonization is the term used to describe those who have drug resistant staph aureus bacteria on or in their bodies but have not yet become ill through the infection of a wound or other area of tissue. The bacteria is often found in the nose, groin or underarm areas.
People can become infected within minutes if they have a wound or existing skin break. But many will carry the bacteria for years and even decades without any skin or wound infection. (1 in 3 people in the population have the easier to treat SA part of MRSA on their skin anyway) The initial colonization could take place through something as simple as sharing a towel.
The strains that are drug resistant and are often detected in hospitals are found on the skin of about 1%, although pockets of the population can have much higher colonization rates. (These include hospital staff, vet personnel and care home residents - between 4-15% of these populations are thought to be MRSA carriers without active infection. This is a conservative estimate)
Those who have the community strains that often infect otherwise healthy people may be part of infection clusters based around social groups living in close proximity or sharing common facilities. These include needle injecting drug users, military staff, prison inmates and warders, students in residence halls, children in day care, those involved in or patronising the sex industry, promiscous heteroseuals and homosexuals and people involved in contact sports. In time people outside these high risks groups will start to become carriers as the bacteria infiltrates all aspects of a society.
People who contract MRSA in hospital may have bacteria transferred into their wound as a result of nursing or surgical proceedures. This is why hand hygiene is so important as the hand can be the transport that carries the bacteria to the wound area. MRSA is also thought to be airborne and can be part of dust or dead skin residues or in the moisture emitted when a person sneezes.
Colonization is usually a more passive state however when the person is well but has become a carrier of the bacteria. It often resides in the groin area, under the arms but especially in the nose. It can set up camp in the throat or some times in the intestine.
Doctors will often seek to decolonize people prior to an operation to help prevent MRSA infection of a wound. This will usually involve bathing with special soap and a nasal cream that is designed to kill the MRSA that often uses the nose as a hiding place.
Because MRSA is becoming so common in some populations doctors are loath to give the nasal treatment to those with simple skin infections or merely carrying the bacteria. This is because of growing resistance patterns with respect to mupirocin, the most commonly used cream. Overuse or unfinished courses of treatment will render the drug useless and will create problems for staff trying to eradicate bacteria prior to an operation.
