April 22, 2014
News Review From Harvard Medical School -- Resistant Staph Bacteria Found in Homes
The "super bug" known as MRSA isn't just in hospitals, prisons and locker rooms. A new study shows that it could be in your home, too. MRSA stands for methicillin-resistant Staphylococcus aureus. These staph bacteria are hard to kill because they resist most antibiotics. MRSA once was found mainly in hospitals and nursing homes. But in recent years it has spread to the community. Some people have been infected in close quarters, such as prisons and locker rooms. The new study focused on 161 New York City residents infected with MRSA. Researchers compared the genetic makeup of MRSA from these people with a group who were not sick. They also tested other household members and social contacts of both groups. Finally, they tested surfaces in people's homes. They found that the homes of people with MRSA were "major reservoirs" of a MRSA strain called USA300. Genes of these bacteria from people in the same home were very similar. But genes of MRSA from different homes varied more. The journal Proceedings of the National Academy of Sciences published the study. HealthDay News wrote about it April 21.
By Howard LeWine, M.D.
Harvard Medical School
What Is the Doctor's Reaction?
The more we use antibiotics, the more we kill off the bacteria that are vulnerable to these drugs. This allows the survivors, called antibiotic-resistant bacteria, to grow and multiply.
Super bugs are strains of bacteria that are no longer affected by most common antibiotics. Of the dangerous super bugs, staph bacteria top the list.
Staph is the short name for Staphylococcus aureus. It's a common kind of bacteria that many people carry on their bodies. This is called colonization. If staph gets under the skin and enters the blood stream, it can be deadly.
When antibiotics were first invented, penicillin could kill staph. Then staph developed resistance to penicillin. That means penicillin could no longer kill it. A newer antibiotic called methicillin was developed that could kill penicillin-resistant staph. But some of these bacteria developed resistance to methicillin, too. They are called methicillin-resistant Staphylococcus aureus, or MRSA.
At first, MRSA was found mostly in hospitals. But it didn't take long before it exploded into the community.
Community-acquired MRSA tends to spread among people who live in crowded conditions or have close skin-to-skin contact. Exposure to cuts and scrapes increases the chance that MRSA will spread. The infection is also spread by poor personal hygiene, not enough hand washing, and sharing contaminated items, such as towels or razors.
MRSA behaves much like other staph. It usually exists in the nose or on the skin without causing disease. But all staph bacteria have the potential to cause trouble. That can range from boils and other mild skin infections to life-threatening lung and blood infections.
When a doctor suspects a person may have a staph infection, he or she can't be sure if it's MRSA or another strain. So choosing the best antibiotic can be a challenge. Because MRSA is now found much more widely, both in and out of the hospital, doctors usually choose an antibiotic that is more likely to kill MRSA. But that can be expensive.
MRSA infections occur more often in the hospital because patients are often less hardy, with weakened immune systems. But why and how is MRSA spreading in the community? Scientists are just beginning to get some answers.
This study provides some important information that helps us better understand the problem. A person carrying MRSA, even without an infection, readily sheds bacteria. They can stick on surfaces at home and then spread to family members. Not aware that they have picked up MRSA, family members then carry it outside the home. That's one way it can spread to people in the community.
What Changes Can I Make Now?
Staph bacteria commonly live in healthy people on the skin and in the nose. But only 2% of people carry MRSA. People carrying MRSA are said to be "colonized" but not infected.
You can help protect yourself from becoming colonized with MRSA. And, if you are colonized, you can help avoid spreading this bug to others.
In your everyday life:
- Wash your hands often and thoroughly throughout the day with soap and water.
- Carry a small bottle of hand sanitizer. Use it when washing your hands is inconvenient.
- Don't share personal items such as razors, towels, sheets and athletic clothing or equipment.
- Keep cuts or scrapes clean. Cover them with bandages.
- Shower after you work out.
- Wash your gym clothes every time you wear them.
- Wash sheets and towels in hot water. Dry them in a hot dryer.
- Take any prescribed antibiotic exactly as directed, and take all of it. Don't save unfinished antibiotics for another time.
In the hospital or other health-care setting:
- Make sure hospital staff wash their hands or use an alcohol-based hand cleaner before they come into your room.
- Clean your own hands often.
- Before a catheter is placed in one of your veins, make sure that your skin is sterilized. Make sure the person inserting the catheter is wearing gloves.
- Make sure all visitors wash their hands or use an alcohol-based hand cleaner before entering the room and again before leaving.
- Observe any precautions requested by hospital staff, such as wearing a gown, gloves or a mask.
What Can I Expect Looking to the Future?
This study has provided new knowledge about MRSA in the home. You can expect future research about what else we might do at home to prevent colonization and spread of this super bug.