WHAT IS MRSA?
Methicillin-resistant Staphylococcus aureus (MRSA) is a specific strain of the Staphylococcus aureus bacterium that has developed antibiotic resistance to all penicillins, including methicillin and other narrow-spectrum penicillin antibiotics. The resistant strain, MRSA was first discovered in the UK in 1961 and is now widespread, particularly in the hospital setting where it is commonly termed a superbug. In Ireland, between 40% and 50% of isolates of Staph Aureus recovered from blood stream infections are methicillin resistant. This is many times higher than some European countries, especially Holland and the Scandinavian countries. MRSA infections are difficult to treat because there are fewer antibiotics which are effective.
The bacterium, Staph Aureus (SA) is very common, and can live in the noses and on the skin of humans. According to research, about 30% of people carry SA in their noses without any ill effects, and will not even be aware of it during their lifetimes. In these cases, people are described as being ‘colonized’. The bacterium is present, but the infection is not active, and the person thus colonized suffers no ill effects. S/he however, is a carrier of the bacterium, and can be a source of infection to other people, especially to those being treated in a health care setting.
In a person who has become ‘infected’ by MRSA, the bacterium has managed to get through the skin through a cut or wound or through the airways. The bacterium can then spread to other parts of the body; it may multiply and cause illness, exposing the patient to a variety of different infections. The majority of people who have MRSA are colonized and it is estimated that one in five will develop an infection.
It is difficult to identify those who are colonized; swabbing and laboratory testing is the only method. Everybody is at risk from infection but some people are more at risk of developing an infection than others. These include:
- Older patients.
- Long term patients or residents in institutions.
- Patients in intensive care.
- Patients who have had surgery.
- Burn victims.
- Patients who have been treated with many antibiotics.
- Diabetics.
- Patients whose immune systems have been compromised.
Detecting infection at an early stage is important as it means that prompt treatment can be given. To this end rapid detection systems have been approved in the United States and Canada, but are still to be adopted here. Early detection is also vital in the prevention of the spread of the bacterium as patients can be screened and isolated if necessary.
The most obvious signs of infection include raised temperature, increased inflammation around a surgical wound, wounds or burns not healing or unusual colour change or odour, coughing or wheezing, mood changes, depression, groin pain, or a burning sensation when urinating. These symptoms can arise from a variety of infections and may not be attributable to MRSA.The infections caused by MRSA can be confined to one part of the body, or can spread to many parts of the body in a generalized fashion. Some of the infections can be minor e.g. sinus infections or boils which do not cause the patient to become very sick. However, others can be more severe and require hospital treatment. These include urinary tract infections, bone and joint infections, cellulitis, and pneumonia.
The transmission of MRSA happens in direct and indirect ways. An example of direct transmission is when a health care worker has some sort of physical contact with a patient who is either colonized or infected with MRSA. The bacterium can find its way on to the hands of the health care worker and be spread when this worker tends to the next patient without having washed her or his hands. Indirect transmission takes place because bacteria can survive in the general environment such as in bedding and on equipment. A health care worker can touch these surfaces and get bacteria on the hands and this is then transmitted to other patients.
To sum up:
- MRSA is a national and international problem which has been said to be endemic in many Irish hospitals.
- Some people who have MRSA are colonized and some are infected.
- MRSA is spread directly through physical contact and from the general environment.
In order to get the problem under control in Ireland the following have been proposed by our leading microbiologists.
- Strict hand hygiene practiced by health care workers and hospital visitors.
- Better and more widespread screening.
- More isolations rooms.
- More infection control nurses.
- Better environmental hygiene.
- More hospital beds to prevent overcrowding.
- Better control of antibiotic prescribing.
- More microbiologists.