Methicillin-resistant Staphylococcus aureus (MRSA) is a bacterium responsible for some difficult-to-treat infections in humans. MRSA is a resistant variation of the common bacteria, Staphylococcus aureus. MRSA is especially troublesome in hospital-acquired (nosocomial) infections. Patients with open wounds and weakened immune systems are at greater risk for infection than general public. MRSA was discovered in 1961and is now found worldwide. MRSA is often referred to in the press as a superbug, but is nothing new. Staph bacteria, like other kinds of bacteria, frequently live on the skin without causing health problems.
Worldwide, an estimated 2 billion people carry some form of Staphylococcus aureus; of these, up to 53 million (2.7% of carriers) are thought to carry MRSA. In the United States, 95 million carry Staphylococcus aureus in their noses; of these, 2.5 million (2.6% of carriers) carry MRSA.
In the United States, there have been increasing numbers of reports of outbreaks of MRSA colonization and infection through skin contact in locker rooms and gymnasiums, even among healthy populations. MRSA has also been found in the public school system of Indianapolis, Indiana and an outbreak in 2003 of the St. Louis Rams football team.
Staphylococcus aureus most commonly colonizes the anterior nares (the nostrils), although the respiratory tract, open wounds, intravenous catheters, and urinary tract are also potential sites for infection. Healthy individuals may carry MRSA asymptomatically for periods ranging from a few weeks to many years. Patients with compromised immune systems are at a significantly great risk of symptomatic secondary infection.
MRSA that is acquired in a hospital is called hospital-associated methicillin-resistant Staphylococcus aureus (HA-MRSA). MRSA infections are now becoming more common in healthy, nonhospitalized persons. This type of MRSA is called community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA).
Causes of MRSA infections are: unnecessary antibiotic use - for decades antibiotics have been prescribed for colds, flu and viral infections that do not require or respond to antibiotics, antibiotics in food – antibiotics are routinely given to cattle, pigs, and chickens, and bacterial mutation – bacteria that survive treatment with one antibiotic may develop resistance to the effects of that drug and similar medicines.
Risk factors for hospital-acquired MRSA include a current or recent hospitlization, residing in a long-term care facility, invasive procedures and recent or long-term antibiotic use. Risk factors for community-acquired MRSA include young age-incomplete development of immune system, participation in contact sports, sharing towels or athletic equipment, having a weakened immune system, such as persons with HIV/AIDS, chemotherapy or chronic prednisone use, living in crowded or unsanitary conditions such as prisons.
To protect yourself, family members, and friends from hospital-MRSA infections: ask hospital staff to wash their hands before touching you, wash your own hands frequently, make sure that intravenous tubes and catheters are inserted and removed under sterile conditions and follow the hospital isolation procedures for gowns, gloves and masks as indicated by signs.
CA-MRSA often results in abscess formation that requires incision and drainage. Before the spread of MRSA into the community, abscesses were not considered contagious. Instead, it was assumed that the infection required violation of skin integrity and the introduction of staphylococci from normal skin colonization. However, newly emerging CA-MRSA is transmissible (similar, but with very important differences) from hospital-acquired MRSA. CA-MRSA is less likely than other forms of MRSA to cause cellulitis.
Both CA-MRSA and HA-MRSA are resistant to traditional anti-staphylococcal antibiotics. CA-MRSA has a greater spectrum of antimicrobial susceptibility, including sensitivity to sulfa drugs, tetracyclines, and clindamycin, i.e. easier to treat. HA-MRSA is resistant even to these antibiotics and often is susceptible only to vancomycin and other newer drugs.
In our hospital, contact precautions signs are placed on the door. The staff and visitors are instructed what the signs mean and how to prevent the spread of the disease. We will also be screening patients at high risk for MRSA by use of cultures, and strict hand washing protocol must be followed by all staff. Alcohol, as well as chlorine bleach, has proven to be an effective topical sanitizer against MRSA. Because MRSA can survive on surfaces and fabrics, including privacy curtains or garments worn by care providers, complete surface sanitation is necessary to eliminate MRSA.
Current U.S. guidelines do not require workers in general workplaces (not healthcare facilities) with MRSA infections to be routinely excluded from going to work. Exclusion from work should be reserved for those with wound drainage that cannot be covered and contained with a clean, dry bandage and for those who cannot maintain good hygiene practices. Workers with active infections should be excluded from activities where skin-to-skin contact is likely to occur until their infections are healed.
