MRSA Furunculosis

MRSA Questions and Answers

1. What is MRSA?

MRSA is an abbreviation for methicillin-resistant Staphylococcus aureus. Approximately 25-30% of healthy people carry the Staph bacteria on their skin or in their noses. Staph bacteria are one of the most common causes of skin infections. Skin lesions frequently begin as pimples and then may grow to form larger areas that become red and tender. These skin lesions are frequently mistaken for spider bites. As they grow they may open up and drain pus.

2. What distinguishes MRSA from other Staph bacteria?

A short history lesson will help explain the answer to this question. Penicillin was thought to be the wonder drug when it was discovered in the 1940’s as it killed the Staph bacteria. However, the bacteria quickly became resistant to penicillin by producing an enzyme that inactivated the antibiotic.

Antibiotics that were effective against the penicillin resistant strains were developed in the 1950’s. Methicillin was the first of these new antibiotics. However, by 1961, strains of Staph that were resistant to methicillin appeared in hospitalized patients. These bacteria were termed methicillin-resistant Staphylococcus aureus, or MRSA, as opposed to the methicillin-sensitive Staphylococcus aureus, or MSSA.

It is important to point out that these resistant Staph bacteria are not new. As stated in the previous paragraph, MRSA were first identified over 45 years ago. What is new is the increasing frequency of these resistant strains among Staph that are isolated in the hospital. In the past, only about 20% of Staph bacteria isolated in hospitals were resistant to methicillin. By 2003, the percentage of hospital-acquired Staph infections that were resistant to methicillin reached 64.4%.

3. If MRSA has been present since the 1960’s, why is there so much attention being given     to it now?

On October 17, 2007, the Journal of the American Medical Association published an article entitled “Invasive Methicillin-Resistant Staphylococcus aureus Infections in the United States”. Based on data collected in this article, MRSA bacteria were estimated to have caused more than 94,000 life-threatening infections and nearly 19,000 deaths in the United States in 2005.

The authors stated in the article that more deaths were associated with MRSA in the United States in 2005 than with AIDS. This statement about the number of deaths related to MRSA made front-page news in the nation’s newspapers, thereby grabbing the attention of the public and the medical community.

However, the headlines did not get across to the public that 85% of these infections occurred in patients that utilized a health-care facility (hospital, nursing home, dialysis center) within the past 12 months. About 14% of the MRSA infections occurred in patients without recognizable health-care facility exposure, and about 1% could not be classified. The vast majority of deaths occurred in hospitalized patients with blood-stream infections or pneumonia. People with skin infections or boils rarely progress to develop the life-threatening illnesses discussed in the article.

4. When did MRSA begin to occur outside of the hospital setting?

Community-associated MRSA infections were first described among injecting intravenous drug users in Detroit in 1981. These bacteria were next associated with the deaths of 4 children in Minnesota and North Dakota in 1997. It was alarming to doctors because patients such as these children who had never been hospitalized were not suspected to be harboring these resistant bacteria.

5. How do you treat MRSA?

Penicillin-based antibiotics such as methicillin, oxacillin, nafcillin and cefazolin are ineffective against MRSA. These infections are treated with antibiotics such as sulfa (Bactrim or Septra), clindamycin, doxycycline, linezolid, rifampin, vancomycin, tigecycline or daptomycin, depending on the type of MRSA infection and the sensitivities determined in the laboratory.

The most common presentation for a Staph infection outside of the hospital is a pimple or boil that may become red, swollen, painful, and drain pus. It is very rare for an otherwise healthy patient to develop a more serious infection such as pneumonia or a blood-stream infection.

According to the Centers for Disease Control and Prevention, 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. Outbreaks have been reported in athletes who share equipment or towels in the locker room or on the field.

Staphylococcal boils are usually treated with warm soaks and drainage. They may spontaneously drain or may require a physician to lance them to drain the pus. If the infection is associated with fever or redness in the skin that spreads beyond the boil, then the patient may also require a course of antibiotics. It is important for your physician to perform a culture of the drainage to see if it is an MRSA. It is not possible to distinguish MRSA from the more sensitive MSSA on appearance alone. It is important to know which strain is causing an infection so that the best antibiotic may be used for each individual case.

Bactrim, clindamycin, doxycycline, linezolid and rifampin are a few of the oral antibiotics that are effective in treating MRSA skin infections, depending on culture and sensitivity results. Sometimes a combination of antibiotics is prescribed. An infectious diseases doctor will interpret the laboratory results and prescribe the appropriate antibiotics if necessary. Not all MRSA bacteria are sensitive to all of these antibiotics. Furthermore, if the incorrect antibiotics are prescribed, the patient may not respond or the patient’s bacteria may develop even more antibiotic resistance.

6. What happens if I get repeated episodes of boils caused by MRSA?

Sometimes your doctor may choose to treat you with a combination of medications in an attempt to decolonize your body of the MRSA. The goal is to rid your body from carrying the bacteria to prevent future recurrences. In one recent trial, this decolonization technique was 70% effective in preventing recurrences.

7. In the hospital I’ve seen doctors and nurses wearing gowns and gloves when taking care of patients with MRSA. Should I to do this at home too?

The purpose of the gowns and gloves in the hospital, also referred to as putting a patient on contact isolation, is to prevent the caregivers from spreading the bacteria on their hands to other patients. Hospitalized patients may be particularly susceptible to getting serious infections because they are already ill and debilitated. Furthermore, they may have devices like intravenous lines and urinary catheters in place that may make it easier for bacteria like MRSA to gain a foothold. At home, it is not necessary to wear gloves and gowns. It is important to maintain good hygiene by washing your hands frequently. If you change bandages on a patient with an MRSA infection, then you should wear gloves and wash your hands thoroughly after changing and discarding the dirty bandages.

8. How do I prevent MRSA infections?

The most important measure to prevent staph infections is to practice good hygiene. People should clean their hands regularly by washing thoroughly with soap and water and drying their hands with a clean towel. People may also use alcohol-based waterless hand sanitizers when soap and water is not available. Keep cuts and scrapes clean and covered with a bandage until healed. Avoid contact with other people’s wounds or bandages. Avoid sharing personal items such as towels, razors and cosmetics. Avoid the use of unnecessary antibiotics that may only serve to increase the risk of antibiotic-resistant bacteria. Athletes should shower before and after practices and games, and should launder their uniforms regularly.

9. Where may I obtain additional reliable information about MRSA?

http://www.cdc.gov/ncidod/dhqp/ar_mrsa_ca_public.html

http://www.state.nj.us/health/cd/mrsa/documents/mrsa_faq.pdf