Invasive group A streptococcus (iGAS)

Question 1

Invasive Group A Streptococcus (iGAS) is a severe infection that occurs when Streptococcus A gets beyond the immune defences of the infected person to infiltrate parts of the body that are typically free from these bacteria, such as the blood, muscles, or lungs. How many cases of iGAS were notified in 2012 in the UK?

1 - 37
2 - 372
3 - 3,729
4 - 37,290

Answer 1

3 - 3,729

Question 2

Which of the following would be a definition of Invasive Group A Streptococcus (iGAS)?

1 - culture isolation of GAS from a normally sterile site
2 - viral load >100,000
3 - bacterial load identified in 3 separate samples
4 - swabs confirming bacteria

Answer 2

1 - culture isolation of GAS from a normally sterile site

Most common sterile culture sites include blood, pleural, pericardial, joint, or cerebrospinal fluid.

Question 3

Invasive Group A Streptococcus (iGAS) is a severe infection that occurs when Streptococcus A bypasses the hosts immune system. iGAS has a myriad of virulence factors that help it avoid the host immune system, BUT which of the following is the main virulence factor?

1 - protein M
2 - streptolysins
3 - streptokinase
4 - hyaluronidase
5 - peptidoglycan
6 - teichoic acid

Answer 3

1 - protein M

Hyaluronic acid capsule of the bacteria is also able to promote antimicrobial peptide resistance and inhibits phagocytosis

Question 4

What is the term used to describe a patient who is otherwise healthy and develops a rapid onset of fever, rash, hypotension, and multi organ system involvement?

1 - Leptospirosis
2 - COVID-19
3 - staphylococcal toxic shock syndrome
4 - enteric fever

Answer 4

3 - staphylococcal toxic shock syndrome

Patients can deteriorate quickly

Question 5

Which of the following is a skin condition causes by Group A Streptococcus?

1 - psoriasis
2 - dermatitis herpetiformis
3 - necrotising fasciitis
4 - squamous cell carcinoma

Answer 5

3 - necrotising fasciitis

Question 6

Invasive Group A Streptococcus (iGAS) have been identified as the pathogen causing which of the following?

1 - measles
2 - dengue fever
3 - scarlet fever
4 - mumps

Answer 6

3 - scarlet fever

Streptococcus Pyogenes causes this by:

• M protein and lipoteichoic acid for attachment
• hyaluronic acid capsule inhibits phagocytosis
• other extracellular products, such as pyrogenic toxin, cause the rash of scarlet fever
  streptokinase, streptodornase (DNase B) and streptolysins

Causes a sore throat, skin infections, skin rash and flu-like symptoms

Question 7

Which of the following can typically be used to diagnose patients with Invasive group A streptococcus (iGAS)?

1 - Culture (throat swab, Blood Culture, fluids)
2 - Serology
3 - antibody testing are anti-streptolysin O
(anti-ASO) and anti-DNase B.
4 - Antigen test
5 - all of the above

Answer 7

5 - all of the above

Question 8

Group A streptococcus can cause all of the following in the image, which can be non-invasive, invasive and post-infectious

Question 8

What kind of rash can Invasive group A streptococcus (iGAS) cause?

1 - lentigo maligna melanoma
2 - erythema migrans.
3 - sand paper rash
4 - herpetiformis dermatitis

Answer 8

3 - sand paper rash

Same as what presents in Scarlett fever