About group A streptococcal

//About group A streptococcal
About group A streptococcal 2017-09-28T09:58:21+00:00

About Group A Streptococcal

What is it?

A bacterium which looks like small round beads under the microscope and which produces an armamentarium of toxins and surface proteins which combat the human immune system and also cause disease. It is also known as Streptococcus pyogenes, S. pyogenes, or simply “group A strep”.

Where does it normally live?

Group A strep normally cause infection in people’s throats and can spread in the community from person to person. 1 – 2% of people may ‘carry’ the bug without knowing and without suffering any illness. Group A strep spreads very easily in conditions where people are housed together in close quarters.

Group A strep also can live on the skin, particularly where the skin is damaged by conditions such as eczema, as well as on any other mucous surface of the body. It cannot survive for very long away from the human body.

What infections can it cause?

Surface Infections

  • Not serious in themselves, but infectious to others
  • Sore throat (pharyngitis) and tonsilitus
  • Impetigo

Complications of surface infections

  • Quinsy or ear infection
  • Scarlet fever
  • Rheumatic fever
  • Sydenhams Chorea
  • Post-strep reactive arthritis
  • Post-strep glomerulonephritis (kidney inflammation)

Deeper infections (Invasive infections)

  • Cellulitis and erysipelas
  • Necrotising fasciitis
  • Myositis
  • Pneumonia
  • Puerperal sepsis (infection around time of childbirth)
  • Rarer infections
  • Bacteremia (bacteria in the blood)

Complications of deeper infections

  • Septic Shock
  • Toxic Shock

Guidelines for prevention and control of group A streptococcal infection in acute healthcare and maternity settings in the UK

Hospital outbreaks of group A streptococcal (GAS) infection can be devastating and occasionally result in the death of previously well patients. Approximately one in ten cases of severe GAS infection is healthcare-associated. This guidance, produced by a multidisciplinary working group, provides an evidence-based systematic approach to the investigation of single cases or outbreaks of healthcare-associated GAS infection in acute care or maternity settings.

The guideline recommends that all cases of GAS infection potentially acquired in hospital or through contact with healthcare or maternity services should be investigated. Healthcare workers, the environment, and other patients are possible sources of transmission. Screening of epidemiologically linked healthcare workers should be considered for healthcare-associated cases of GAS infection where no alternative source is readily identified. Communal facilities, such as baths, bidets and showers, should be cleaned and decontaminated between all patients especially on delivery suites, post-natal wards and other high risk areas. Continuous surveillance is required to identify outbreaks which arise over long periods of time. GAS isolates from in-patients, peri-partum patients, neonates, and post-operative wounds should be saved for six months to facilitate outbreak investigation. These guidelines do not cover diagnosis and treatment of GAS infection which should be discussed with an infection specialist.

Read the full guideline here.

Crown Copyright © 2011 Published by Elsevier Ltd on behalf of The British Infection Association. All rights reserved.

Further Information

Very rarely, streptococci acquired on the skin can go on to cause more serious disease. Once on the skin, group A streps can enter the deeper parts of the body, by “by-passing” the body’s normal immune defences and by using special ‘tools’ to invade through the barriers covering our body, such as the skin. They are often helped by co-existing conditions which might cause skin breaks, such as chicken pox, or a surgical wound, or even a tiny crack between the toes, such as those sometimes seen with athletes foot.

Wherever the bacteria settle, there will be local inflammation. The body will recognise the bacteria as a danger, and the immune system will send in white blood cells to fight the infection, leading to inflammation. It is the inflammation that alerts us to the presence of an infection.

Who is at risk of invasive group A strep infections?

Although there are recognised groups of people at risk from invasive group A strep infection (skin conditions which allow bacteria in, or medical illnesses which put them at greater risk), almost one third have no risk factors whatsoever.

Predisposing skin conditions.

  • Surgery/recent injury
  • Injecting drug use
  • Chicken pox

Predisposing Medical conditions.

  • Heart disease
  • Diabetes
  • Alcoholism
  • Cancer
  • Lung disease
  • HIV infection
  • Pregnancy
  • No risk factors (30%)

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