What is MRSA?
MRSA stands for methicillin-resistant Staphylococcus aureus. The term is used
to describe a number of strains of the bacteria, Staphylococcus aureus, that
are resistant to a number of antibiotics, including methicillin.
Staphylococcus aureus is a group of bacteria that live on the surface of people's
skin and inside the nose. It is normally harmless. Most people who are carrying
it are totally unaware that they have it. In fact, it is thought that up to
30% of the general UK population carries these bacteria in their nose or on
their skin.
What is Nosocomial infection?
Nosocomial infection is the term used for infection originating in hospital
and is a major problem in many health care facilities, with approximately
1 in 10 patients acquiring an infection during a hospital stay. MRSA is now
endemic in many hospitals, and is one of the leading causes of nosocomial
pneumonia and surgical site infection and the second leading cause of nosocomial
blood stream infections.
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How is it spread?
Although most nosocomial infections are associated with person-to-person contact,
it has been estimated that the airborne route of transmission accounts for
between 10% and 20% of endemic nosocomial infections. Common factors associated
with acquiring MRSA in any acute care setting include prolonged hospital stay,
use of broad spectrum antibiotics, greater number and longer duration of antibiotic
use, stay in an ICU or burn unit, surgical wounds, decubitus ulcers, poor
functional status and proximity to another patient with MRSA. MRSA can colonize
the anterior nares, skin, wounds, and in rare instances the rectum of infected
or colonized persons. Healthcare workers’ hands, the environment, and
airborne transmission (in the case of staphylococcal pneumonia) are the most
common means of spreading MRSA. However, with the exception of tuberculosis,
where the airborne route of infection has long been recognised, the contribution
made by airborne pathogens towards nosocomial infection has often been underestimated.
Despite this, it is now recognised that a number of nosocomial pathogens,
including Aspergillus spp., Acinetobacter spp and MRSA can be transmitted
by the airborne route.
Who is most at risk?
People with weakened immune systems (for example due to other illnesses) or
who have undergone surgery (for example heart surgery or hip replacement)
can develop serious problems. Populations that are more susceptible to MRSA
colonization, given other risk factors, include intravenous drug users, persons
with dermatological diseases, or diabetes, and persons on renal dialysis.
What is antimicrobial?
An antimicrobial is a substance that that kills or slows the growth of microbes
such as bacteria (antibacterial activity), fungi (antifungal activity), viruses
(antiviral activity), or parasites (antiparasitic activity). The term originally
described only those formulations derived from living organisms but is now
applied also to synthetic antimicrobials.
What are viruses, and what are bacteria?
A virus is a poison and the term is applied to a group of infective agents
which are so small they are able to pass through the pores of collodian filters.
They are responsible for some of the most important diseases affecting mankind,
e.g. influenza, poliomyelitis, smallpox and yellow fever. A virus is normally
not treatable with antibiotics. Viruses are 
transmitted
both by physical contact as well as through the air. They are normally invisible.
Bacteria is equivalent to terms such as germs, microbes and micro-organisms. They are larger in structure than viruses and usually are visible microscopically. They can be treated by antibiotics except when they have become resistant to such treatment, as is the case of Staphylococcus aureus (MRSA). Bacteria can also be transmitted through the air.
What are the effects of MRSA?
MRSA may invade the blood and cause potentially serious complications such
as bacteremia, septic shock, and serious metastatic infections (endocarditis,
pneumonia, osteomyelitis, and arthritis). In more vulnerable people, Staphylococcus
aureus bacteria have been known to cause boils, abscesses, impetigo, septic
wounds, heart-valve problems and toxic shock syndrome. In extreme cases, it
can result in death.
How much of a problem is MRSA?
MRSA was first reported in the UK and Europe in the 1960’s and in the
USA in 1968. In the UK it is estimated that at least 100,000 hospital acquired
infections occur each year. MRSA accounts for 52.3% of S. aureus nosocomial
infections in USA, is now endemic in many hospitals, and is one of the leading
causes of nosocomial pneumonia and surgical site infection and the second
leading cause of nosocomial blood stream infections. MRSA in particular has
become a major problem in many UK hospitals. An MRSA support group said that
the UK Government's tally of 5,000 deaths a year comes from statistics compiled
in 1994. Their analysis of statistics from official bodies suggests that the
real number of annual deaths is closer to 20,000.
What is being done to combat MRSA?
Re-training of hospital cleaning staff, tighter cleaning and disinfection
policies, the appointment of a “Super-Nurse” by the UK Government
and general hygiene awareness programmes are the main tools for combating
the spread of MRSA in UK hospitals.
What is the current estimated cost to the NHS due to MRSA related
infections?
Estimated costs to the NHS of hospital acquired infections run at approximately
£1 billion. In the USA in 1999, MRSA treatment costs were estimated
to be 6-10% more than treating an MSSA infection (resulting from the increased
cost of vancomycin use and costly isolation procedures), and that the attributable
death rate of MRSA was 21% as compared to 8% in MSSA.
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Significance of Airborne Transmission of Methicillin-Resistant Staphylococcus
aureus in an Otolaryngology–Head and Neck Surgery Unit 
"Measures should be taken to prevent the spread of airborne MRSA to control nosocomial MRSA infection in hospitals."
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The Times
In a letter to The Times newspaper published 4th March 2005, six eminent microbiologists expressed their concern at the generally accepted view that better hygiene is the key to fighting MRSA. Cleaner hospitals and more frequent hand-washing, though desirable, will not solve the problem. They point out that MRSA spreads on tiny skin particles carried in the air and that "to be truly effective, measures to contain MRSA must block airborne transmission".
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Below is an extract from THE USE OF ENGINEERING MEASURES TO CONTROLAIRBORNE PATHOGENS IN HOSPITAL BUILDINGS by Dr Clive Beggs, School of Civil Engineering, University of Leeds, Leeds LS2 9JT, UK
"Although
most nosocomial infections are generally associated with person to person
contact, there is increasing evidence that many nosocomial infections
are transmitted via an airborne route. Indeed, it has been calculated
that the airborne route of transmission accounts for 10% of all sporadic cases
of nosocomial infection (Brachman, P. S. Nosocomial infection –
airborne or not?). However, with the exception of TB, where the airborne
route of infection has long been recognised, the contribution made by airborne
pathogens towards nosocomial infection has often been underestimated. Despite
this, it is now recognised that a number of nosocomial pathogens, including
Aspergillus spp., Acinetobacter spp and MRSA can be transmitted by
the airborne route." Click
here to read in full