MRSA Infections

Q: I've heard a lot about MRSA in the news lately. Does it only appear on the skin, or can it also affect the internal organs as well? How can I prevent infection?

A: Best known for its link to infected areas of the skin that are tender, red and swollen, methicillin-resistant Staphylococcus aureus (MRSA) has the potential to infect other areas of the body, including the lungs, urinary tract, bloodstream, heart valves and bones. While less common, the spread of MRSA throughout the body is more likely to occur in those individuals with a weakened or impaired immune system, especially if the infection was acquired in a hospital or other healthcare setting. Fortunately, most cases of MRSA can be successfully treated.

What is MRSA?

MRSA is a strain of Staphyloccus aureus bacteria that is resistant to certain types of antibiotics. It normally doesn't penetrate healthy and intact skin, but can move through open areas such as cuts, scratches, wounds or skin ulcers. Two routes for potential infection include direct skin-to-skin contact with an open and infected wound containing MRSA, or through direct contact with an object (such as a doorknob, towel, or razor) contaminated with MRSA.

What forms of MRSA are common?  

Healthcare-associated MRSA is the most common form and is more likely to occur in older individuals who are hospitalized, living in nursing homes, or undergoing dialysis in a treatment center. These individuals have a higher risk for serious illness.

Community-associated MRSA tends to affect healthy and younger individuals living or working in crowded and close quarters. Skin infections are more common, but it does have the potential to spread, especially to the lungs. 

Who's at risk?

Even though MRSA infections can occur anywhere and affect anyone, the following situations can increase the risk:

• A compromised or poorly functioning immune system
• Hospitalization for 14 days or longer  
• Living in a long-term care facility
• Continuous use of a urinary catheter or other medical device providing a direct link from outside to inside the body

Additionally, the Centers for Disease Control and Prevention stated that MRSA skin infections are more common in settings with the Five Cs:

• Crowding
• Frequent skin-to-skin Contact
• Compromised skin (cuts, etc.)
• Contaminated items and surfaces
• Lack of Cleanliness

What are the signs and symptoms?

A MRSA infection may initially appear as a small, red and tender area of skin that resembles a bug bite or pimple. However, as the infection spreads, it often grows into a skin abscess (pus under the skin), carbuncle (larger than an abscess with several openings to the skin), or boil (pus-filled area around a hair follicle).

Needless to say, any such progression is concerning and should be evaluated by a physician. Other signs that an infection is present include the following:

• Fever
• Yellow/white or greenish drainage that may have a foul odor
• Tender red/dark pink area on the surface of the skin that is growing in size

Additionally, the following symptoms may indicate the infection has spread:

• Shortness of breath (concern for pneumonia)
• Shaking chills (infection of the blood or heart valves)
• Severe headache that is different from your normal headache patterns
• Extreme weakness and low blood pressure
• Joint pains accompanying any of the above symptoms

While these descriptions sound scary, remember that the majority of MRSA infections are localized to the skin and often respond well to treatment. That said, your doctor may suggest a blood culture (checking for an infection in the blood), urine culture, tissue or fluid sample from the skin, and/or samples of mucous from the nose. These samples would be tested for the presence of MRSA.

If the results are positive, treatment options range from draining the pimple-like area or boil with sterile and specialized equipment, to the use of specific antibiotics for the more widespread and potentially serious type of MRSA infections. The medications selected are known to be effective against the specific strain of MRSA and may include vancomycin, linezolid, trimethoprim-sulfamethoxazole, doxycycline, tetracycline or clindamycin.

Prevention measures

It's clear that we can't remove these germs from our environments, but we can minimize their potential health impact through the practice of healthy hygiene as follows:

• Periodically wash your hands for 15 to 20 seconds with regular soap (antibacterial varieties are not necessary) and water throughout the day, especially before and after eating, toileting and handling dirty clothes.
• Use hand sanitizers containing at least 60 percent alcohol if soap and water are not available.
• Use disposable gloves when touching cuts or wounds.
• Avoid the use of shared personal items such as razors, sheets, athletic equipment, towels and clothing (unless clean and washed).
• Keep all wounds clean and covered with a sterile dressing. Open wounds may allow harmful bacteria to enter, while draining and uncovered wounds may be a potential source of infection to others.
• Do not use public whirlpools or saunas if you have an open wound.
• Clean shared sporting equipment before and after use.
• Ask all healthcare providers (doctors, nurses, laboratory and respiratory personnel, others) to wash their hands before examining or assisting you.

Why is MRSA on the rise?

One of the problems leading to the rise in MRSA infectons is the overuse or "misuse" of antibiotics. As a result, the immune systems of many individuals have lost their effectivness to kill or eradicate this type of infection. To help prevent the continuation of this trend, physicians should only prescribe antibiotics for bacterial infections that require treatment. Also, patients must take and finish the antibiotics as directed when properly prescribed.

Additionally, other sources of sntibiotics may be causing the trend of bacterial resistence. Antibiotics used in livestock eventually end up in our water systems.   

For further information on MRSA, please speak with your physician and review the informaton found at the Centers for Disease Control and Prevention or The Mayo Clinic.

More about MRSA on MSN Health & Fitness:

• Combatting MRSA
• Superbug Test Detects MRSA Faster
• 7 Everyday Biohazards
• Climate Change and the Spread of Infectious Diseases

Find all articles by Dr. Rob.

Do you have a health question you'd like to ask Dr. Rob? Send e-mail to experts@microsoft.com. Please include Ask Dr. Rob in the subject line.

Each of our experts responds to one question each week and the responses are posted on Mondays on MSN Health. We regret that we cannot provide a personalized response to every submission.

Robert Danoff, D.O., M.S., is a family physician and program director of The Family Practice Residency, as well as the combined Family Practice/Emergency Medicine Residency programs at Frankford Hospitals, Jefferson Health System, Philadelphia, Pa. He is the medical correspondent for CN8, The Comcast Network, a regular contributor to Discovery Health Online and a contributing writer to The New York Times Special Features. (Read his full bio.)