MRSA, or methicillin-resistant Staphylococcus aureus, is a bacterium that has developed antibiotic resistance, first to penicillin in 1947, and later to methicillin and related "anti-staph drugs". Popularly termed a "superbug", it was first discovered in Britain in 1961 and is now widespread. While an MRSA colonisation in an otherwise healthy individual is not usually a serious matter, infection with the organism can be life-threatening to patients with deep wounds, intravenous catheters or other foreign-body instrumentation, or as a secondary infection in patients with compromised immune systems.
Because cystic fibrosis patients are often treated with multiple antibiotics in hospital settings, they are often colonised with MRSA, potentially increasing the rate of life-threatening MRSA pneumonias among them. The risk of cross-colonisation has led to increased use of isolation protocols among these patients.
In the US there are increasing reports of outbreaks of MRSA colonisation and infection through skin contact in locker rooms and gymnasiums, even among healthy populations. MRSA causes as many as 20% of Staph aureus infections in populations that use intravenous drugs. These out-of-hospital strains of MRSA, now designated as community-acquired, methicillin-resistant staph. aureus, or CAMRSA, are not only difficult to treat but are especially virulent. CAMRSA apparently did not evolve de novo in the community, but represents a hybrid between MRSA which escaped from the hospital environment and the once easily treatable community organisms. Most of the hybrid strains also acquired a virulence factor which makes their infections invade more aggressively, resulting in deep tissue infections following minor scrapes and cuts, and many cases of fatal pneumonia as well.
As of early 2005, the number of deaths in the United Kingdom attributed to MRSA has been estimated by various sources to lie in the area of 800 to 955 per year.
A last-resort antibiotic, vancomycin, is used to kill MRSA, but several new strains of the bacterium have been found showing antibiotic resistance to vancomycin; those new evolutions of the MRSA bateria are dubbed "Vancomycin Intermediate-resistant Staphylococcus aureus" (VISA).
From the US CDC's MRSA Fact Sheet:
- "How are staph and MRSA spread? - Staph bacteria and MRSA can spread among people having close contact with infected people. MRSA is almost always spread by direct physical contact, and not through the air. Spread may also occur through indirect contact by touching objects (i.e., towels, sheets, wound dressings, clothes, workout areas, sports equipment) contaminated by the infected skin of a person with MRSA or staph bacteria."
and
- "Are staph and MRSA infections treatable? - Yes. Most staph bacteria and MRSA are susceptible to several antibiotics. Furthermore, most staph skin infections can be treated without antibiotics by draining the sore. However, if antibiotics are prescribed, patients should complete the full course and call their doctors if the infection does not get better. Patients who are only colonised with staph bacteria or MRSA usually do not need treatment."
Initiatives
At the end of August 2004, after a successful pilot scheme to tackle MRSA, the British National Health Service announced its Clean Your Hands campaign. Wards will be required to ensure that alcohol-based hand rubs are placed near to all beds so that staff can hand wash more regularly. It is thought that if this cuts infection by just 1% the scheme will pay for itself many times over. [1]
See also
Last updated: 05-21-2005 14:41:44
