Methicillin-resistant Staphylococcus aureus (MRSA) is a strain of S. aureus that is resistant to the usual antibiotics used for Staph infections.
People at Increased Risk
Groups of people who have a higher risk of developing MRSA infections include those who have been exposed to many antibiotics, people who live in crowded quarters, and those who have frequent skin-to-skin contact with other people who may be infected. These at-risk groups include:- Athletes who play contact sports
- Military personnel
- Men who have sex with men
- Prison inmates
- IV drug users
- Homeless people
- Children in daycare centers
The 5 (or 6) C's of CA-MRSA Transmission
Sporadic outbreaks of Community Acquired MRSA (CA-MRSA) infections have led to the development of a model of transmission. This model gives us factors that can increase a person's risk of contracting a MRSA infection. The risks are:- Contact: Skin to skin contact with someone who is infected or colonized
- Cleanliness: Poor personal hygiene or not covering infected wounds
- Compromised Skin Integrity: Breaks in the skin from cuts, abrasions, or dermatitis
- Contaminated Objects: Contact with fomites like razors, doorknobs, towels, or clothes
- Crowded Living Conditions: When there are large numbers of people in a small space, it's easier for MRSA to spread from person to person.
- Capsules: Some suggest a 6th C, antibiotic capsules. Use of antibiotics that treat Methicillin-sensitive Staph aureus but not MRSA seem to especially increase the risk of infection.
Controversies about MRSA Infection Risk
Some investigators say nasal colonization should be another risk factor, but it may not be as important as once thought since infection can spread from skin-to-skin contact or contact with a contaminated surface.While researchers have identified risk factors for contracting a MRSA infection, we don't definitively know which ones are more likely to cause an infection or not. In one study, it appeared that CA-MRSA infections were more often connected with skin breaks and contact with infected people, but overall, it is hard to perform a study that accurately examines the small details associated with common risks.
Sources:
Gould, IM. “Antibiotics, skin and soft tissue infection and methicillin-resistant Staphylococcus aureus: cause and effect.” Int J Antimicrob Agents. 34 Suppl 1(2009): S8-11.
Miller, LG, and SL Kaplan. “Staphylococcus aureus: a community pathogen.” Infectious Disease Clinics of North America. 23(2009): 35-52.
