Staphylococcus aureus: what is it and which risks associated to it?

Staphylococcus aureus, or S. aureus, is a common bacterium that lives on the skin or in the nose. It is also called golden staph. In most situations, S. aureus is harmless. However, if it enters the body through a cut in the skin, it can cause a range of mild to severe infections, which may cause death in some cases.

Common infections caused by golden staph include:
(1) boils and abscesses – infections of the skin
(2) impetigo (school sores) – a highly contagious, crusty skin infection that may affect newborn babies and schoolchildren.

More serious infections include:
(1) meningitis – infection of the membranes lining the brain
(2) osteomyelitis – infection of the bone and bone marrow
(3) pneumonia – infection of one or both lungs
(4) septic phlebitis – infection of a vein
(5) endocarditis – infection of the heart valves.
(6) drug-resistant strains of golden staph

A bacterial infection consists of countless individual bacteria. Most infections caused by golden staph are treatable with antibiotics. However, there is a strong possibility that a few bacteria will survive a course of antibiotics, perhaps due to a gene mutation. The antibiotic-resistant golden staph bacteria that remain then flourish, since they no longer have to compete for resources with the rest of the colony.

Resistant strains of golden staph are known as multi-resistant S. aureus (MRSA) or multi-resistant organisms (MROs). MRSA stands for meticillin-resistant Staphylococcus aureus. It is sometimes known as a superbug. There are various strains (subtypes) of S. aureus and some strains are classed as MRSA. MRSA strains are very similar to any other strain of S.aureus. That is, some healthy people are carriers and some people develop the types of infections described above.

Most S. aureus infections can be treated with commonly used antibiotics. However, MRSA infections are resistant to an antibiotic called meticillin and also to many other types of antibiotics. Resistance means that the germs (bacteria) are not killed by the antibiotic. MRSA has become much more common since the 1980s. MRSA is now the cause of over 4 in 10 bloodstream infections with S. aureus....