What is it? 

Methicillin-resistant Staphylococcus aureus (MRSA) is an infection caused by Staphylococcus (staph) bacteria. Staphylococcus aureus is a common bacteria which is generally harmless. However, if it multiplies uncontrollably, MRSA infection occurs.

MRSA is no more virulent than other strains of Staphylococcus aureus, although its antibiotic resistance makes it more challenging to treat when infection occurs. The excessive or inappropriate use of antibiotics has encouraged the development of MRSA.

What are the symptoms? 

Infections with MRSA cause different symptoms depending on the part of the body affected. Infected skin often appears swollen, warm, red, and painful when infected with MRSA. MRSA skin infections often resemble spider bites or pimples and can be mistaken for them. In most cases, the site has a yellow or white centre and a central head. Redness and warmth may surround an infected area, a condition known as cellulitis.

The affected area may drain pus and other fluids. Some people also experience a fever.

Without laboratory tests it is often difficult to determine if an infection is caused by MRSA or another type of bacteria.

Transmission 

The most common route of transmission of MRSA is from resident to resident via the hands of employees who acquire the organism after direct resident care or after handling contaminated items.

Common sites for MRSA colonisation are nostrils, axilla, perineum, wounds, ulcers and skin. Body sites more resistant to MRSA eradication include tracheostomy sites, chronic leg ulcers, wounds, and rectal and perineal regions.

Colonisation with MRSA is unlikely to lead to infection unless the colonised person is immunocompromised or has been treated with immunosuppressive therapy AND given antibiotics that suppress normal flora and allows MRSA to multiply. 

Diagnosis

To diagnose MRSA, Doctors examine tissue samples or nasal secretions for signs of drug-resistant bacteria.