Streptococcus
Streptococcus: A Comprehensive Guide to the Bacterial Pathogen
Introduction
Streptococcus is a genus of Gram-positive bacteria that are commonly found on the skin and in the respiratory and gastrointestinal tracts of humans and animals. While some species of Streptococcus are harmless, others can cause a wide range of infections, including strep throat, scarlet fever, and pneumonia.
Description
Streptococcus bacteria are spherical or ovoid in shape and form chains or pairs. They are facultative anaerobes, meaning they can grow with or without oxygen. Streptococcus species can be divided into several groups based on their Lancefield classification, which is determined by the presence of specific antigens on their cell walls. The most common groups that cause human infections are:
- Group A Streptococcus (GAS): Causes strep throat, scarlet fever, and toxic shock syndrome.
- Group B Streptococcus (GBS): Can cause infections in newborns, including pneumonia and sepsis.
- Group C Streptococcus: Can cause respiratory infections, skin infections, and bloodstream infections.
- Group D Streptococcus: Mainly associated with endocarditis (infection of the heart valves).
- Group G Streptococcus: Can cause skin and soft tissue infections, and less commonly, invasive infections.
Associated Diseases
Streptococcus bacteria can cause a variety of infections, including:
- Strep throat: Caused by GAS and characterized by severe sore throat, fever, and swollen lymph nodes.
- Scarlet fever: A complication of strep throat caused by the production of toxins by GAS. Symptoms include a rash, fever, and sore throat.
- Pneumonia: A lung infection that can be caused by GAS, GBS, or other Streptococcus species.
- Meningitis: An infection of the membranes that cover the brain and spinal cord.
- Endocarditis: An infection of the heart valves, which can be caused by Group D Streptococcus.
- Toxic shock syndrome (TSS): A rare but life-threatening condition caused by toxins produced by GAS. Symptoms include fever, rash, low blood pressure, and organ failure.
- Impetigo: A skin infection that causes blisters and sores.
Did you Know ?
- Approximately 10% of school-aged children carry GAS in their throats at any given time.
