Streptococcus

Definition

Streptococcus is a genus of Gram-positive bacteria that often occur in chains or pairs. They are known for causing a variety of infections in humans, ranging from mild throat infections to life-threatening diseases.

5 Must Know Facts For Your Next Test

1. Streptococcus species are classified into groups based on their hemolytic properties and serological characteristics.
2. Group A Streptococcus (GAS) is responsible for strep throat, scarlet fever, and rheumatic fever.
3. Group B Streptococcus (GBS) can cause severe infections in newborns, such as meningitis and sepsis.
4. Streptococcus pneumoniae is a major cause of bacterial pneumonia and meningitis in adults.
5. Many Streptococcus species are part of the normal microbiota of the human skin, respiratory tract, and digestive system.

Review Questions

• What are the different classifications of Streptococcus based on?
• Which Streptococcus group is associated with infections in newborns?
• Name two diseases caused by Group A Streptococcus.

Related terms

Hemolysis: The breakdown of red blood cells; used to classify Streptococci.

Gram-Positive Bacteria: Bacteria that have a thick peptidoglycan cell wall which retains the crystal violet stain during the Gram staining process.

Normal Microbiota: The community of microorganisms that reside on or within various parts of the body without causing disease.