GABHS

Group A beta-hemolytic streptococcus (GABHS) Group A beta-hemolytic streptococcus (GABHS), also known as Streptococcus pyogenes, is a species of Gram-positive bacteria that is responsible for a variety of human diseases. These bacteria are characterized by their ability to cause complete hemolysis (beta-hemolysis) when grown on blood agar plates, which is a key diagnostic feature.

Characteristics

GABHS are cocci that typically form chains. They are facultative anaerobes, meaning they can survive in both aerobic and anaerobic environments. The bacteria are catalase-negative, which helps differentiate them from Staphylococcus species.

Pathogenesis

GABHS is known for causing a range of diseases, from mild superficial infections to severe systemic illnesses. Some of the common diseases caused by GABHS include:

• Pharyngitis (strep throat)
• Scarlet fever
• Impetigo
• Cellulitis
• Necrotizing fasciitis
• Rheumatic fever
• Post-streptococcal glomerulonephritis

Virulence Factors

GABHS possesses several virulence factors that contribute to its pathogenicity:

• M protein: A major virulence factor that helps the bacteria evade the host's immune system.
• Streptolysins: Toxins that cause the lysis of red and white blood cells.
• Streptokinase: An enzyme that breaks down blood clots, facilitating the spread of the bacteria.
• Hyaluronidase: An enzyme that degrades connective tissue, aiding in the spread of infection.

Diagnosis

Diagnosis of GABHS infections typically involves:

• Rapid antigen detection test (RADT)
• Throat culture
• Blood tests to detect antibodies

Treatment

Treatment of GABHS infections usually involves antibiotics, with penicillin being the drug of choice. In cases of penicillin allergy, alternatives such as erythromycin or clindamycin may be used.

Prevention

Preventive measures include:

• Good hygiene practices, such as regular handwashing
• Avoiding close contact with infected individuals
• Prompt treatment of strep throat to prevent complications

Related Pages

• Streptococcus
• Pharyngitis
• Scarlet fever
• Impetigo
• Necrotizing fasciitis
• Rheumatic fever
• Post-streptococcal glomerulonephritis