The National Academies: What You Need To Know About Infectious Disease

The National Academies

What You Need To Know About Infectious Disease


Methicillin-resistant Staphylococcus aureus, or MRSA, is a type of staph bacteria that has become resistant to antibiotics commonly used to treat ordinary staph infections, including penicillin, amoxicillin, and oxacillin. At one time, MRSA infections only affected people in health care settings, largely because patients in these facilities typically have weakened immune systems and are undergoing procedures such as surgery and the insertion of catheters, making it easier for MRSA to enter the body. These infections are often severe, which is why health care personnel must follow strict procedures about hand washing and proper catheter care.

MRSA infections now also occur in the community at large. In those instances, they typically take the form of skin infections and are most likely to be spread in places where people are in close contact with each other, such as schools, locker rooms, and correctional facilities. The biggest risk factor is open or broken skin. However, MRSA infections can occur even on areas of the skin where there is no visible wound or break. In addition, MRSA can get into small openings in the skin, such as the openings at hair follicles.

MRSA infections can occur in any geographic area and anywhere on a person’s body. The MRSA bacteria tend to reside on people’s bodies and are not naturally found in the environment (e.g., soil, the ocean, lakes). Objects can be contaminated if someone touches infected skin or areas of the body where these bacteria can live (like the nose) and then touches the object. People may be infected by touching these surfaces but not in all instances. Direct contact with a person’s skin infection is another way that MRSA can spread.

In health care settings, MRSA infections tend to be more severe, causing life-threatening illnesses such as bloodstream infections, surgical site infections, and pneumonia. Symptoms can vary widely, depending on what form of infection is taking place and what stage it is in. Outside of health care settings, MRSA typically causes skin infections. These may first appear as small red bumps resembling pimples, boils, or spider bites. They can rapidly turn into deep, painful abscesses that require surgical draining. The bacteria may remain in the skin but sometimes it moves deep into the body, causing potentially life-threatening infections in bones, joints, surgical wounds, the bloodstream, heart valves, and lungs. They commonly occur where there has been visible skin trauma (cuts or scrapes, for example) and areas of the body covered by hair (back of neck, groin, buttock, armpit, beard area of men).

MRSA bacteria still respond to certain antibiotics. As with regular staph infections, recognizing and treating MRSA infections early reduces the risk of severe infection. Treatment will vary depending on the location of the infection and its severity. Treatment of skin infections may include draining the infection and an antibiotic prescription. Those who suspect they might have a MRSA skin infection should not attempt to treat it themselves. If you are given an antibiotic, be sure to finish the entire course unless told otherwise by your physician. It is possible to get repeat infections; once you have had a MRSA infection it does not mean you are immune to future infections.

Personal hygiene can help prevent getting MRSA skin infections. Keep hands clean by washing thoroughly with soap and warm water or with an alcohol-based hand sanitizer. Keep cuts and scrapes clean and covered until healed. Avoid contact with other people’s bandages. Avoid sharing personal items such as towels and razors. Use a barrier, such as clothing or towels, between you and any surfaces you share with others (such as gym equipment), and shower immediately after activities that involve direct skin contact with others. These are easy ways to decrease your risk of getting MRSA. Additional preventive measures are recommended for health care settings, athletic environments, and correctional facilities. They can be found at


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What do you know about infectious disease?

The human papillomavirus (HPV) causes about what percentage of cervical cancer cases?

  • Sorry, that’s incorrect.

    The human papillomavirus (HPV) causes more than 90% of cervical cancer cases.

  • Sorry, that’s incorrect.

    The human papillomavirus (HPV) causes more than 90% of cervical cancer cases.

  • Correct!

    The human papillomavirus (HPV) causes more than 90% of cervical cancer cases.

Infectious Disease Defined

Autoimmune Disease
A condition in which the immune system mistakenly attacks healthy tissue in the body.

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