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 live in people’s throats and can spread in the community from person to person. Often, up to 15% 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
- Sore throat (pharyngitis)
- Impetigo
Complications of surface infections
- Scarlet fever
- Rheumatic fever
- Sydenhams Chorea
- Post-strep reactive arthritis
- Post-strep glomerulonephritis (kidney inflammation)
Deeper 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
Surface infections caused by Group A strep.
A proportion of those carrying the bug might develop a sore throat with swollen tonsils. If severe, this might be associated with fever and swollen glands in the neck. This is particularly common amongst children, possibly because they haven’t yet developed immunity to the bug. It is extremely rare for a sore throat infection to progress to anything more serious. Treatment involves detecting the bug (e.g. from a throat swab) and giving antibiotics to cure the infection.
Occasionally, a child may develop a reddish rash during a strep sore throat, which goes pale on pressing; this is known as ‘scarlet fever’ and is quite rare now. Some children and young adults develop recurrent problems with group A strep sore throat, and occasionally some have their tonsils removed to reduce this recurrence. Some children are troubled by group A strep infections around the vulva, vagina, or even the anus.
The child might complain of soreness, itching, and discharge. Provided that a swab is taken for testing, the condition can be easily treated with the correct antibiotics. It is likely that the streps carried in the throat are the source for these types of infections.
Simple ‘surface’ skin infections with group A strep can be troublesome but can be readily dealt with by antibiotic treatment; examples include impetigo. All of these conditions may provide a source of streptococci that can go on to infect others. Repeated or untreated strep infections, in particular sore throat, can be associated with a number of complications caused by our immune responses to the bug. Examples include rheumatic fever (which can affect the heart valves, brain, skin, and joints), post-strep reactive arthritis and glomerulonephritis (kidney inflammation). All of these conditions are unusual in the U.K. but are fairly common in developing countries where strep infections are commoner.
For Part 2,
Recognised complications following streptococcal surface
infections, Please Click HERE
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