Streptococcus Pyogenes

Question 1

Describe the microbiology of strep pyogenes.

Answer 1

• gram positive cocci
• arranged in chains
• group A streptococcus
• facultative

Question 2

What are the virulence factors of strep p?

Answer 2

• bacterial capsule
• exotoxin production (e.g. Streptolyisn S) and immune evasion
• dissemination

Question 3

What are the common strep p infections?

Answer 3

• sore throat
• cellulitis
• scarlet fever
• meningitis
• pneumonia

Question 4

What are the differential diagnoses of strep throat?

Answer 4

• Glandular fever: viral infection
• Cancer: persistent sore throat
• Quinsy: painful collection of pus
• Epiglotittis: inflammation of epiglottis

Question 5

What are the danger symptoms of sore throat?

Answer 5

• persistent high temp
• symptoms for longer that 4-5 days
• difficulty swallowing or breathing

Question 6

What is the treatment for strep throat?

Answer 6

OTC analgesics and antibiotics

• Carbimazole
• DMARDS

Question 7

What are the complications of Group A Strep infections?

Answer 7

• acute rheumatic fever
• rheumatic heart disease
• post streptococcal glomerulephritis
• bacteraemia / septicaemia
• necrotising fasciitis
• TSS

Question 8

What are the risk factors for cellulitis?

Answer 8

• obese
• weakened immune system
• poorly controlled diabetes / circulation problems
• chickenpox or shingles
• lymphoeddema
• IV drug use
• previous episodes of cellulitis

Question 9

What are the endogenous carriers of Gp A streptococci?

Answer 9

• interdigital toe spaces
• vagina
• anus

Question 10

What are the differential diagnosis for cellulitis?

Answer 10

• eczema
• lymphoedema
• allergic reaction

Question 11

What is the treatment for mild/moderate cellulitis infections?

Answer 11

7-14 days antibiotics at home

- Phenoxymethylpenicllin (clarithromycin / clindamycin)

Question 12

What is the treatment for advanced cellulitis infection?

Answer 12

IV benzylpenicillin (vancomycin)

Question 13

What are the potential complications of cellulitis?

Answer 13

• bacteraemia / septicaemia
• necrotising fasciitis
• abscess
• facial cellulitis
• meningitis