Bay Area Medical Information
MRSA
Methicillin Resistant Staph aureus
Microscopic view of
Staph aureus:
On this page:
MRSA under microscope
Photo courtesy of the
CDC/Janice Carr
Prevention is key: Ten simple steps to avoiding a serious infection  


The best prevention is through the practice of good hygiene:

  • Good hand-washing habits are key to prevention. HandwashingSkin that is intact on your hands will not become infected from MRSA, but hands are a good vector for transmission of the bacteria to your mouth or an open area somewhere on your skin. Washing your hands thoroughly with soap and water or using an alcohol-based hand sanitizer is one of the most effective steps to prevention. Always carry a small bottle of sanitizer for times when washing at a sink is not possible. Use your hand sanitizer as soap if the bar of soap at the sink happens to look suspiciously dirty. Use a paper towel to turn off the faucet after washing, and then open the bathroom door with a paper towel as well. Public restrooms are increasingly locating the garbage can near the door for this purpose.
  • Be aware of surfaces that can be contaminated, such as door knobs, grocery cart handles, elevator buttons, TV remote controls, telephones, the pen at the check-out counter, computer keyboards, and a handshake are all common vectors for transmission of both bacteria and viruses. The bathroom floor and the child's seat in grocery carts are frequently contaminated with a variety of bacteria and viruses. Women often lay their purse in these areas and then later place their purse on their lap or on the kitchen countertop.
  • Public toilet seats should be considered a potential vector and care should be taken to either avoid sitting down on it or use a protective barrier.
  • Athletic equipment should be cleaned frequently and sterilized, if possible, on a regular basis. Young athletes should shower after each practice or game, and not share towels.
  • Exercise equipment in gyms could also theoretically transmit the bacteria if the circumstances were right. Wipe surfaces of equipment clean before and after use and place a barrier such as a towel or clothing between your skin and shared equipment. An immediate shower after working out is important.
  • Wear shower shoes in public showers.
  • Keep cuts and scrapes clean and covered with a bandage until healed. An opening in the skin is the ideal route for Staph to invade and start an infection. Any break in the skin does not need to be "open to the air" to heal, in fact healing occurs most quickly when the wound is covered.
  • Avoid contact with other people’s bandages, wounds, abrasions, raised bumps, bug bites, pimples, inflamed hair follicles, ulcerations, or any area that is open, reddened or draining.
  • Refrain from sex if there are any skin lesions or open areas
  • Avoid sharing personal items such as towels, shower shoes, razors, tweezers, nail clippers, bar soap, or clothing that may have had contact with the infected wound or bandage. Wash sheets, towels, and clothes with water and laundry detergent. Drying in a hot dryer, rather than air-drying, also helps kill bacteria and viruses.
What is MRSA?

Also referred to as "Super Bugs" or "flesh-eating bacteria", methicillin-resistant Staphylococcus aureus (MRSA) infections are a growing concern in the United States and pose new challenges for healthcare professionals. MRSA are a type of "staph" bacteria that are resistant to most oral antibiotics. Thus the term "methicillin-resistant". Methicillin includes several types of penicillin. When methicillin, and other common antibiotics, are unable to kill the bacterial infection, it becomes much harder to eradicate. MRSA infections require treatment with newer antibiotics, such as intravenous vancomycin, although newer strains of the bacteria are becoming resistant to newer antibiotics as well.

Staphylococcus aureus, or "staph," are bacteria often carried on the skin or in the nose of healthy people. While 25% to 30% of the population is colonized with staph, approximately 1% is colonized with MRSA (staph that is resistant to methicillin). Colonized refers to the presence of bacteria that are not causing an infection.

Staph can be transmitted from both infected or colonized people to other people either through the air or on contaminated hands, skin, and objects. Most MRSA infections are minor and go away without any medical treatment, however some can be invasive and even progress to life-threatening disease.

MRSA infections are more difficult to treat than ordinary staph infections, and they also tend to be more virulent. A recent analysis involving patients with MRSA infections and patients with drug-sensitive Staphylococcus aureus, found that the MRSA patients were 36% more likely to die and stayed in the hospital seven days longer than the patients who had the less virulent drug-sensitive strain of a Staph aureus infection.

Most cases of MRSA are minor and resolve with little or no intervention, however some infections are invasive and can spread to internal organs via the bloodstream. These are the infections that are the most concerning and the subject of a recent report from the CDC which reveals that they may be more common than previously suspected. Infections with MRSA are approaching epidemic levels in some parts of the United States, according to the CDC. The highest rates are in the southern parts of the U.S., including Atlanta, Los Angeles and Texas.

Where did it come from?

MRSA was first seen in hospitals and healthcare facilities such as nursing homes and dialysis centers, where the patients have weakened immune systems. Now, ominously, a new strain is emerging with a growing number of outbreaks and deaths in settings such as prisons, day care facilities, military units, competitive sports teams, and more recently in the general community. A significant number of those affected with this new strain have had to be hospitalized for what appeared to be a simple but persistent skin infection or for a lung infection that is secondary to a case of influenza.The community-acquired MRSA has clinical and microbiological features that are unlike the hospital version in that it has become more easily transmissible and more virulent. In other words, much more dangerous.

Currently, MRSA causes more hospital-acquired infections than any other organism and is the most common drug-resistant bug in North America, Europe, North Africa, the Middle East, and East Asia. Antibiotic resistance in hospitals worldwide threatens to leave medical and public health workers virtually helpless in the prevention or treatment of many infections. Resistance means that people with infections are ill for longer periods, and are at greater risk of dying, and that disease epidemics are prolonged.

" A major cause of the antibiotic resistance crisis is the uncontrolled and inappropriate use of antibiotics globally. They are used by too many people to treat the wrong kind of infections at the wrong dosage and for the wrong period of time."(7) Approximately 70 percent of all the antibiotics used in the United States are used as feed additives for chicken, hogs, and beef cattle. Antibiotic feed additives are used without a prescription to help animals grow slightly faster -- and to compensate for crowded, often unsanitary conditions on industrial-scale farms. Drug resistant bacteria and other microbes are passed through the food chain to the consumer, where they may cause disease, or transfer the resistance to human pathogens.Six reports recently published by the National Institutes of Health warned about this practice and its impact on human health. The scientists' recommendations included a ban on using antibiotic feed additives to promote the growth of livestock and a new requirement that the drugs be available to farmers only by prescription. Europe already has banned the use of antibiotics to promote livestock growth.(6,7)

Four large US poultry producers -- Perdue , Tyson , Gold Kist , and Foster Farms report that they no longer use antibiotics to promote growth. The U.S. government, however, does not collect data on antibiotic use in agriculture, so there is no way to verify these statements.(8)

Signs and symptoms of MRSA

Staph bacteria, including MRSA, most often infect the skin with localized skin infections that may look like a pimple, a spider bite, or a boil and can be red, swollen, painful, and possibly have pus or other drainage. Especially concerning are whitish pus-filled areas when there is associated fever or a general feeling of illness. Another warning sign is when skin infections seem to be passing from one family member to another or if two or more family members have skin infections simultaneously.

Staph infections, particularly community-acquired MRSA infections, can be dangerously virulent, however, and result in more invasive skin infections, and infect other areas of the body as well. MRSA can cause external and internal abscesses and spread into the blood (bacteremia or sepsis - which is life-threatening), bones (osteomyelitis), lungs (staphylococcal pneumonia), heart (endocarditis – which can damage the heart valves), and other organs. In a recent study, researchers describe a necrotizing pneumonia that can occur from a MRSA infection in the lungs which results in an aggressive condition that often kills patients within 72 hours.(3)

Abscess located on the hip of a prison inmate, which had begun to spontaneously drain, releasing its purulent contents. The abscess was caused by methicillin-resistant Staphylococcus aureus bacteria, (MRSA).arrow Abscess on hip from MRSA Cutaneous abscess on the knee of a prison inmate, which had been caused by methicillin-resistant Staph aureus arrow
Both photos are courtesy of the CDC
Abscess on knee from MRSA
Treatment

Contact your health care provider if you think you have a staph infection.

Treatment of mild staph infections may be with topical or oral antibiotics. Many staph skin infections may be treated by draining the abscess or boil and may not require antibiotics. Drainage of skin boils or abscesses should only be done by a healthcare provider.

Treatment of MRSA infections require special types of antibiotics, some of which must be given through veins (intravenously) when initially treating serious or life-threatening infections.

If after visiting your healthcare provider the infection is not getting better after a few days, contact them again. If other people you know or live with get the same infection tell them to go to their healthcare provider.

Home care and precautions (6)
  1. Keep the wound covered: Keep wounds that are draining or have pus covered with clean, dry bandages. Pus from infected wounds can contain staph. So keeping the infection covered will help prevent the spread to others. Bandages or tape can be thrown away with the regular trash.
  2. Wash your hands thoroughly with warm water and soap after changing the bandage or touching the infected wound. You, your family, and others in close contact should wash their hands often with soap and warm water. You can use an alcohol hand gel when soap and water are not available.
  3. Do not share personal items. Avoid sharing personal items such as towels, washcloths, razors, tweezers, nail clippers, or clothing that may have had contact with the infected wound or bandage. Wash sheets, towels, and clothes with warm water and laundry detergent. Dry clothes in a hot dryer, rather than air-drying. This also helps kill bacteria.
  4. Do not prepare or serve food for others if you have wounds or skin infections on your hands or wrists (5)
  5. Take medication as prescribed by your health care provider and carefully follow any further instructions on proper care of the wound. Be sure and tell any other health care provider, who treat you, that you have or had a staph skin infection. If the type of staph infection you have is MRSA, be sure to tell them this as well.
MRSA can be easily spread

Factors that have been associated with the spread of MRSA skin infections include: close skin-to-skin contact, openings in the skin such as cuts or abrasions, contaminated items and surfaces, crowded living conditions, and poor hygiene.

Transmission of MRSA infections are most often occuring in crowded areas where there's a tendancy for people to come into contact with infected items and then spread the infection to others such as in athletic settings, prisons and the military. Young athletes who are sharing sports equipment are particularly vulnerable. They are playing contact sports where sweating and breaks in the skin are common place giving MRSA a typical portal of entry.

A growing number of cases have occurred from shaving in sensitive areas that creates infected hair follicles. MRSA has been increasingly identified in these small pimples and boils. Skin-to-skin contact with these areas can then transmit the MRSA bacteria to another person. Researchers from Columbia University Medical Center, recently identified three cases in which the community-associated MRSA was transmitted between heterosexual partners.(4) Physicians in the community are increasingly seeing various skin lesions growing MRSA, as well as sexually transmitted MRSA ulcerations. In a letter published in the Annals of Emergency Medicine in January, a physician reported treating a lap dancer with MRSA infections on her buttocks. The patient reported that other lap dancers at her club also had similar problems, and this problem is now considered a known occupational hazard by the lapdancers. In this case, it would seem that toilet-seats and exercise equipment in a health club could also be a vector for transmission.

More about Staph aureus...
Food Poisoning: Staph aureus has the ability to make seven different toxins that are frequently responsible for food poisoning

Staphylococcal food poisoning is caused by eating foods contaminated with toxins produced by Staphylococcus aureus. The most common way for food to be contaminated with Staph is through contact with food workers who carry the bacteria or through contaminated milk and cheeses. For example, a cook with a Staphylococcal skin lesion on his hand can easily contaminate the food he's preparing. Once in the food, the bacteria will then multiply and produce toxins that can cause a gastrointestinal illness in as little as 30 minutes.

Symptoms most often develop within one to six hours after eating contaminated food and usually include one or more of the following: nausea, vomiting, stomach cramps, and diarrhea. The illness is usually mild and most patients recover after one to three days. In a small minority of patients the illness may be more severe.

Staph Food Poisoning Preventive measures are very important:
  • Wash hands and under fingernails vigorously with soap and water before handling and preparing food.
  • Do not prepare food if you have a nose or eye infection.
  • Do not prepare or serve food for others if you have wounds or skin infections on your hands or wrists (5)
Infectious Diseases in the News

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References

(1) "Vigilance Urged for Community-Acquired MRSA" MedPage Today, March 2006
(2) "MRSA" from the CDC, October 2007
(3) "Staph Toxin Can Trigger Deadly Pneumonia" Medline Plus, January 2007
(4) Clinical Infectious Diseases, Feb 1, 2007
(5) "Staphylococcal Food Poisoning" from the CDC, March 2006
(6) "What do we feed to food production animals?" Environmental Health Perspectives, February 2007
(7) "Antibiotic Resistance" Press Release from the World Health Organization (WHO) 2007
(8) "Subtracting an Additive" The Boston Globe, Feb 11, 2007

Written by N Thompson, RN, MSN, ARNP and M Thompson, MD, Internal Medicine, Last updated January 2010


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