What Is Methicillin Resistant Staphylococcus Aureus (MRSA)?

Have you ever wondered why doctors advise you to take the entire course of the prescribed antibiotics without missing a day? Or not to reuse leftover antibiotics? There is a good reason for this. Doing these things can weaken the effectiveness of antibiotics and lead to antibiotic resistance.

Methicillin-resistant Staphylococcus aureus (MRSA) is an example of an antibiotic-resistant infection that has resulted from the misuse and overuse of antibiotics. Keep reading to find out more about MRSA, its causes, how can you identify if you have an MRSA infection and how it can be treated.


Methicillin-resistant Staphylococcus aureus (MRSA), commonly referred to as the “superbug”, is a type of staph infection. This bacteria belongs to the Staphylococcus aureus (S.aureus) group and was discovered in 1961 in England as a result of its resistance to the antibiotic methicillin.1,2  Ever since the discovery of MRSA and the development of new treatment strategies, the prevalence of it has reduced to 1-3% in the entire UK population. 

S. aureus bacteria causes common and usually harmless skin infections. Most of the time, S. aureus is found on the skin, nose, groin or armpits of healthy individuals without causing any infection. However, when it enters the body through a cut or wound, the bacteria can cause severe infections.2,3

In the UK, MRSA infections tend to spread within communities that have direct or indirect contact with hospitals, nursing/care homes and other healthcare institutions. But the spread of the infection can vary based on a person’s exposure to different public settings.

MRSA infections are categorised into two types based on how it is acquired:3

  1. Healthcare-associated MRSA (HA-MRSA): This variant of MRSA is more common in healthcare facilities such as dialysis clinics, nursing homes, and hospitals. A greater risk of acquiring HA-MRSA exists in patients who are in hospitals or who have recently undergone medical treatment, such as surgery or dialysis. These infections frequently have a more serious course and are sometimes antibiotic-resistant
  1. Community-associated MRSA (CA-MRSA): This kind of MRSA infection occurs in communal settings, such as schools, gyms, and houses. Athletes, service members, or children who often interact with others in these environments run an increased risk of contracting CA-MRSA. Although these infections often aren't as severe, certain antibiotics may still be unable to treat them

MRSA infection spread occurs through direct skin-to-skin contact, a contaminated environment, or infected objects. Especially in the dust, MRSA bacteria may persist for a very long time making it an air-borne infection. It is important to maintain good hygiene if you or people around you are exposed to the above-mentioned settings.2,3 

Causes of MRSA infection

The primary cause of the MRSA bacteria evolving is due to overexposure (through overuse or inappropriate use) to antibiotics, which over time results in the development of antibiotic resistance. The bacteria adapts and evolves to existing antibiotics and develops mechanisms to resist their effects. As a result, the antibiotics have become less effective and the bacteria has become more difficult to treat.1,2,3

The MRSA bacteria is resistant to beta-lactam antibiotics, such as methicillin, in particular. The bacteria produces a protein called penicillin-binding protein 2a (PBP2a) which makes it difficult for the antibiotic to bind to the bacteria and kill it, allowing the bacteria to continue to grow and cause infection.2,3

Similar to common S.aureus bacteria, MRSA can be found harmlessly existing on 1 in 30 people’s skin, and is medically referred to as “colonisation” or “carrying MRSA”. But it is seen to cause very serious infections if it enters a person’s body via a wound or surgical opening. Some individuals are at a higher risk of developing an MRSA infection: Risk factors include:1,2,3

  • Hospitalisation or living in a long-term care facility
  • Recent surgery or invasive medical procedures such as dialysis or chemotherapy
  • Individuals with a wound, burn, feeding tube, drip into a vein, or urine catheter 
  • Individuals with weak immune systems due to pre-existing conditions such as HIV/AIDS, cancer, or diabetes
  • Chronic skin conditions, such as eczema or psoriasis
  • If you work as a veterinary professional, agricultural labour or animal caretaker. 
  • Injection drug use
  • Close contact with someone who has MRSA

It is important to remember that MRSA infections are often not a problem for healthy people, including children and pregnant people. However, you can ask your doctor for precautionary measures against MRSA if you have been recently hospitalised, undergone surgery, or taking treatments that could weaken your immune system.

Signs and symptoms of MRSA infection

The signs and symptoms of MRSA infection may vary in each individual depending on the kind and severity of the infection. These infections can range from milder skin infections to pneumonia and sepsis.

Some commonly observed signs and symptoms of MRSA infection are:2

  • Red, swollen, and painful skin which can be warm to the touch
  • Bumps or boils that are filled with pus
  • Fever (high temperatures)
  • Chills
  • Fatigue
  • Headache
  • Overall body and muscle aches
  • Rash that looks like a pimple or spider bite

Not everyone with MRSA will experience all of these symptoms, and some people may have no symptoms at all. If you suspect you may have MRSA, it's important to minimise contact with people and seek medical attention immediately.

Management and treatment for MRSA infection

The management and treatment of MRSA infection depend on the severity of the infection, the patient's pre-existing conditions and the patient's overall health. Treatment typically involves a combination of powerful antibiotics, wound care, and supportive/preventive measures.

The common course of treatment and management strategies for MRSA infection are:2,4,5

  • Antibiotics: Antibiotics that are efficient against MRSA, such as vancomycin, linezolid, daptomycin, or ceftaroline, are often the first-line therapy for MRSA infections. Antibiotic combinations are given in 7-10 day courses and personalised for each individual. Depending on the nature and severity of the illness as well as any underlying medical issues the patient may have, different antibiotics may be recommended
  • Treating infected wounds: A boil or abscess that has been infected with MRSA has to be cleaned up and drained. This can be done by a medical practitioner using sterile techniques to prevent the infection from spreading. The wound will be covered with a clean, dry bandage to help prevent the spread of infection
  • Supportive measures: Supportive measures may be required in addition to antibiotics and wound care to assist treat the signs and symptoms of MRSA infection. Those who have pneumonia, for instance, are given oxygen therapy or breathing treatments, whereas patients who have bloodstream infections will be given intravenous fluids or other supportive medications
  • Decolonisation of MRSA found on skin: Decolonisation involves applying antibacterial cream inside the nose and washing with an antibacterial shampoo at first. Then clothes, bedding, and towels should be changed every day and should be washed separately at a high temperature to prevent reinfection. These steps are observed at home when undergoing treatment or done before hospitalisation 

If there are no symptoms seen, MSRA infections become harder to be diagnosed earlier. In such advanced cases, MRSA infections can be very difficult to treat, especially if the bacteria have become resistant to multiple antibiotics. In these cases, more aggressive treatments may be necessary, such as surgical removal of infected tissue or the use of experimental therapies (clinical trials).2


How is MRSA infection diagnosed?

MRSA infection is diagnosed based on a physical examination, medical history, and laboratory testing like swabbing and testing of the infected region for MRSA bacteria. The results will be available in a few days and your GP will administer the required treatment.4

How can I prevent MRSA infection?

MRSA infection may be avoided by following good hygiene habits such as routine hand washing, avoiding close contact with infected people, and keeping wounds clean and covered.

Who is at risk of MRSA infection?

Those with weak immune systems, people working in healthcare and veterinary environments, and anyone who is in direct contact with someone who has MRSA infection is at increased risk.

How common is MRSA infection?

In the UK, MRSA infection is seen in 1-3% of the population and MRSA colonisation is seen in 1 in 30 people. It is commonly seen in healthcare settings.

What are the types of MRSA infections?

Healthcare-associated MRSA (HA-MRSA) and community-associated MRSA (CA-MRSA) are the two types of MRSA infections.

When should I see a doctor?

If you develop symptoms of a skin infection, especially if the area is red, warm, and painful, you should see a GP. Visit A&E if you develop symptoms such as high fever or difficulty breathing.


Methicillin-resistant Staphylococcus aureus (MRSA) commonly known as "superbug", is a type of staph infection that is resistant to a wide range of antibiotics. The misuse and overuse of antibiotics is the primary cause of the MRSA bacteria. The symptoms of MRSA infections can range from minor skin infections to more serious infections like pneumonia. An individual may get infected in a hospital setting (HA-MRSA) or community setting (CA-MRSA). Antibiotics, wound care, and supportive therapies are frequently used in combination for treatment. It's important to visit your GP if you suspect to have an MRSA infection. Make sure you practice good hygiene and take steps to prevent future infections. You should keep in mind that the sooner you discover an MRSA infection, the easier it will be to cure and provide preventive care.


  1. Lee AS, De Lencastre H, Garau J, Kluytmans J, Malhotra-Kumar S, Peschel A, Harbarth S. Methicillin-resistant Staphylococcus aureus. Nature reviews Disease primers. 2018 May 31;4(1):1-23. Available from: https://www.nature.com/articles/nrdp201833
  2. Siddiqui AH, Koirala J. Methicillin resistant Staphylococcus aureus. InStatPearls [internet] 2021 Jul 19. StatPearls Publishing. Available from: https://www.ncbi.nlm.nih.gov/books/NBK482221/
  3. Pantosti A, Venditti M. What is MRSA?. European Respiratory Journal. 2009 Nov 1;34(5):1190-6. Available from: https://erj.ersjournals.com/content/34/5/1190.long
  4. Choo EJ, Chambers HF. Treatment of methicillin-resistant Staphylococcus aureus bacteremia. Infection & chemotherapy. 2016 Dec 1;48(4):267-73. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5204005/
  5. Brown NM, Goodman AL, Horner C, Jenkins A, Brown EM. Treatment of methicillin-resistant Staphylococcus aureus (MRSA): updated guidelines from the UK. JAC-Antimicrobial Resistance. 2021 Mar;3(1):dlaa114. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8210269/
This content is purely informational and isn’t medical guidance. It shouldn’t replace professional medical counsel. Always consult your physician regarding treatment risks and benefits. See our editorial standards for more details.

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Jeffy Joseph Vinohar

MSc. Oncology, University of Nottingham, England

Jeffy is an aspiring academic scientist with a bachelors in Biomedical sciences, Biotechnology with a keen interest in cancer studies. During her masters she aimed to learn more about making healthcare accessible and solutions to reduce healthcare inequalities in the field of oncology.
She currently interested in paediatric neuro-oncology and developing less invasive therapeutics for it by obtaining a PhD in coming years, while being involved with simplifying scientific research into health awareness articles.

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