The streptococcus or 'strep' bacteria cause streptococcal infections. These can affect anyone, from babies to older adults. Streptococcal infections may require antibiotic treatment and can range from mild to life-threatening.
Symptoms depend on the kind of infection and the part of the body affected.
Streptococcus infections may be more likely in people less able to fight off infections, such as people with weakened immune systems.
Streptococci infections are divided into groups:
Group A streptococcus
Group A streptococcus bacteria, also called GAS, tend to affect the throat, skin, anus and genital tract.
The bacteria spreads from close contact with an infected person through droplets in the air, skin contact, contaminated surfaces, objects or food.
This causes conditions including:
- Cellulitis, an infection of the deeper layers of skin causing infected areas to look red and swollen and to feel painful and hot.
- Ear infections.
- Erysipelas, a form of cellulitis affecting the upper skin layers.
- Impetigo, a highly contagious bacterial skin infection causing blisters and sores.
- Necrotising fasciitis, affecting a layer of connective tissue, known as the superficial fascia that lies beneath the skin and between muscles and organs in the body. The infection can spread aggressively, causing tissue death.
- Pneumonia, inflammation or swelling in the lungs in which the air sacs fill with pus and other fluids.
- Sinusitis, affecting the sinuses behind the nose.
- Scarlet fever, a rare bacterial illness causing a pink-red rash that feels like sandpaper.
- Sore throat or pharyngitis.
- Tonsillitis, affecting the tonsils. Bacterial tonsillitis is sometimes called strep throat.
Group B streptococcal infections
Group B streptococcal infections, or GBS, are part of the normal bacterial flora in the gut and genital tract. However, they can cause dangerous diseases in newborn babies, including meningitis, septicaemia and pneumonia.
During pregnancy, these bacteria can also lead to the loss of a baby through septic abortion.
Group C & G streptococcal infections
These bacteria often cause infections of the throat, skin and soft tissue in the body. They spread from an infected person by sneezes, coughs or contact with an open wound.
These infections include:
- Bacteraemia, bacteria in the blood
- Bone infections
- Endocarditis, inflammation of the lining of the heart
- Joint infections
- Toxic shock.