Meticillin resistant Staphylococcus aureus (MRSA)

Key points

Staphylococcus aureus is a common bacterium that lives harmlessly on the skin and in the nose of about a third of the population. Most strains of Staphylococcus aureus are sensitive to the more commonly used antibiotics and are known as meticillin sensitive Staphylococcus aureus (MSSA). If the Staphylococcus aureus strain is resistant to the more commonly used antibiotics it is known as meticillin resistant Staphylococcus aureus (MRSA).

Both MRSA and MSSA are not a danger to healthy individuals, but people may become colonised. This is when bacteria settle at a particular site on the body without producing an immune response and there are no signs of infection. However, Staphylococcus aureus may cause serious infections such as bacteraemia (blood poisoning).

Screening required for:

• patients with a previous history of MRSA (isolate patient until screen obtained)
• patients that have undergone surgical procedures within the last month
• patients admitted from another hospital facility
• patients admitted from a nursing or residential care home facility
• intravenous drug user
• patients who self-harm (breaking the skin within the last month)
• patients with chronic wounds for example, leg ulcers
• patients with indwelling devices, for example, urinary catheters.

Screening sites

• Nose, use a blue swab. One swab to be used for both anterior nares (fleshy part of the nose). The swab can be pre-moistened if required by using the gel provided with the swab or with sterile water.
• Groin, use a separate blue swab. One swab to be used for both sides of the groin.
• Skin lesions or wounds, using a charcoal swab one swab to be taken from each site, the site and type of wound must be clearly identified for example, self-injurious wound to left arm or un gradable pressure ulcer to right heel. Note: if there are clinical signs of infection the swab needs to be labelled for microscopy, culture and sensitivity as it may be a different organism causing infection.
• Invasive devices, one swab from each insertion site, for example, PEG, intravenous catheter, suprapubic catheter or tracheostomy site.

Transmission

• People who are colonised can act as carriers and pose a risk of cross infection, especially to other vulnerable people.
• The bacteria can pass from one person to another by direct contact. The organism can also be shed into the environment, where other individuals may then acquire it.

Treatment

• Colonisation:
  • suppression treatment recommended in hospital, skin and nasal decolonisation
  • not usually recommended for patients in the community except those at higher risk of developing infection
  • colonisation can lead to infection
• Infection:
  • most patients with MRSA will be colonised rather than infected and do not require systemic antibiotics
  • however, if a wound or insertion site is displaying signs of infection, obtain a swab of the area for ‘culture and sensitivity’
  • if systemic treatment is required seek advice from the consultant microbiologist

Antimicrobial therapy

As antimicrobial use is a recognised risk factor for MRSA acquisition, all patients with MRSA should have their antibiotic therapy reviewed, and any unnecessary antimicrobial agents should be stopped.

MRSA bloodstream infection

MRSA Blood stream infection (BSI), sometimes called MRSA bacteraemia, occurs when bacteria invade the bloodstream through a variety of different routes such as:

• breaks in the skin for example, cuts or surgical incisions
• indwelling devices, for example, urinary catheters, intravenous cannulae
• localised sites of infection, for example, infection in the urinary tract or the lung that spills over into the bloodstream

BSIs can be short-lived and patients can remain asymptomatic. These short lived BSIs normally go unnoticed and are cleared rapidly by the body’s immune system and are called ‘transient’ or ‘silent’ bacteraemia.

BSIs can however persist for days and weeks and lead to patients being severely ill with clinical signs of sepsis (for example, fever, rigor). In these instances successful treatment relies on eradicating or treating.

IPC precautions

• Enhanced precautions required, this includes a higher level of standard precautions but not necessarily full isolation precautions. Please discuss with the IPC team.
• Although isolation is not usually required the patient should be cared for in a single room.
• Placement in a bay will require a risk assessment to be completed and other patients in the bay must not have any wounds or invasive devices.
• Treat linen as contaminated (red alginate bag) and waste as infectious (orange waste bag).
• At least once daily clean with chlor-clean (1,000 ppm).
• Enhanced cleaning in the areas where the patient has been on the ward with Clinell universal wipes.
• Notify the IPC team of any confirmed inpatient cases:
  • Phone: 03000 214872
  • Email: rdash.ipcteam@nhs.net

Page last reviewed: November 18, 2024
Next review due: November 18, 2025