Staphylococcal infections are a group of infections caused by the bacterium Staphylococcus. You may have heard them referred to as "staph infections".

Staph bacteria can cause a wide range of infections, from relatively minor skin infections such as boils, to more serious infections of the blood, lungs and heart.

There are many types of Staphylococci, but most infections are caused by a group called Staphylococcus aureus.

This group of bacteria includes meticillin-resistant Staphylococcus aureus (MRSA), which is resistant to certain antibiotics that are commonly used for staph infections, such as flucloxacillin.

It also includes PVL-Staphylococcus aureus, which produces a toxin called Panton-Valentine leukocidin (PVL), which kills infection-fighting white blood cells and can cause recurrent skin infections, such as boils and abscesses.

This page covers some of the main types of staph infection, including information on how these infections are spread and treated.

Types of staph infections

Staph infections can be broadly classified into two groups: skin and soft tissue infections, and invasive infections. Examples are given below.

Skin and soft tissue infections

Most infections caused by staph bacteria are relatively minor and only affect the skin or underlying tissue. Common examples include:

  • boils – red, painful lumps on the skin that usually develop on the neck, face, armpit or buttocks
  • impetigo – a highly contagious skin infection that mainly affects children, which can cause sores, blisters and crusts to develop on the skin
  • cellulitis – an infection of the deep layers of the skin, which can cause affected areas to quickly become red, painful, swollen and hot
  • skin abscess – a collection of pus that appears as a painful lump under the surface of the skin
  • folliculitis – an infection of a hair follicle (small sac in the skin that a hair grows from), which causes an itchy pus-filled bump to develop
  • wound infections – an infection of a cut or graze or surgical wound, causing redness, swelling, pain and pus
  • staphylococcal scalded skin syndrome (SSSS) – a more serious condition that mainly affects babies and young children, where staph bacteria release a toxin that damages the skin, leading to extensive blistering that looks like the skin has been scalded

Click on the links above for more information on these conditions, including their symptoms and treatments.

Invasive infections

In a small number of people, a staph skin infection can lead to a more serious, invasive infection deeper within the body. Examples include:

  • septic arthritis – a joint infection that causes pain, swelling, redness and tenderness in affected joints
  • osteomyelitis – a bone infection, usually affecting one of the legs, causing bone pain, restricted movement, and swelling, redness and warmth in the affected area
  • pneumonia – an infection of the lungs that causes persistent coughing, breathing difficulties and chest pain; this often occurs after a viral illness such as flu
  • endocarditis – an infection of the inner lining of the heart, causing a fever, chest pain, coughing, weakness and shortness of breath
  • sepsis – an infection of the blood that causes a high temperature (fever), rapid heartbeat and rapid breathing
  • toxic shock syndrome – where bacteria release toxins into the blood, which can cause a sudden fever, vomiting, diarrhoea, faintingdizziness, confusion and a rash

Click on the links above for more information about these conditions, including their symptoms and treatments.

How you get a staph infection

Staph bacteria are common. About one person in every three carries the bacteria harmlessly on their skin, usually inside their nose and on the surface of their armpits and buttocks.

However, the bacteria can cause problems if they enter the body through a break in the skin, such as a cut or grazeburn or insect bite. They can also get into your body via medical equipment, such as urinary catheters, openings in the skin where drips are inserted and feeding tubes.

Staph bacteria are usually spread between people through close skin contact or by sharing contaminated objects, such as towels or toothbrushes. Occasionally, they can be spread in droplets in the coughs and sneezes of someone carrying the bacteria.

Eating food contaminated with staph bacteria can give you food poisoning. This normally develops after eating food, usually meat, that hasn't been cooked or stored properly.

Who is affected

Staph skin infections are common, particularly among children, teenagers and young adults. Invasive infections are much rarer.

Both types of infection can affect healthy people, but more serious infections tend to affect those who:

  • have a weakened immune system because of an underlying medical condition or a side effect of treatment, such as chemotherapy
  • use medical equipment that goes directly inside their body, such as a urinary catheter
  • have experienced severe trauma to the skin, such as a deep wound or a major burn

Treating staph infections

Some minor staph infections, including minor boils and food poisoning, don't need specific treatment and will get better on their own within a few days or weeks.

In some cases, antibiotic tablets or creams may be recommended to treat the infection, and you may need a minor procedure to drain any pus from under your skin, using a needle or scalpel.

Until the infection clears up, you should take precautions to avoid spreading the infection to other people. These include washing your hands regularly, not sharing objects that could become contaminated, regularly cleaning any pus off your skin, and covering the infected area with a dressing or plaster.

Invasive staphylococcal infections will often require treatment in hospital, because your body's functions may need to be supported while the infection is treated. The infection will usually be treated with antibiotic injections for several days.

Preventing staph infections

You can reduce your chances of developing staph infections by:

  • washing your hands with soap and warm water regularly – particularly if you come into contact with someone who has a staph skin infection
  • keeping your skin clean by having a bath or shower every day
  • keeping any cuts clean and covered
  • not sharing towels, washcloths, bed linen, toothbrushes and razors
  • ensuring that food is both properly cooked and properly chilled – read more about preventing food poisoning

If you experience repeated staph infections and you're found to carry the bacteria on your skin, your doctor may recommend using antibacterial shampoo and nasal cream to kill the bacteria and reduce the risk of further infections.

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The information on this page has been adapted by NHS Wales from original content supplied by NHS Choices.
Last Updated: 07/12/2016 11:15:25