Streptococcus Pyogenes Flashcards
Describe the microbiology of strep pyogenes.
- gram positive cocci
- arranged in chains
- group A streptococcus
- facultative
What are the virulence factors of strep p?
- bacterial capsule
- exotoxin production (e.g. Streptolyisn S) and immune evasion
- dissemination
What are the common strep p infections?
- sore throat
- cellulitis
- scarlet fever
- meningitis
- pneumonia
What are the differential diagnoses of strep throat?
- Glandular fever: viral infection
- Cancer: persistent sore throat
- Quinsy: painful collection of pus
- Epiglotittis: inflammation of epiglottis
What are the danger symptoms of sore throat?
- persistent high temp
- symptoms for longer that 4-5 days
- difficulty swallowing or breathing
What is the treatment for strep throat?
OTC analgesics and antibiotics
- Carbimazole
- DMARDS
What are the complications of Group A Strep infections?
- acute rheumatic fever
- rheumatic heart disease
- post streptococcal glomerulephritis
- bacteraemia / septicaemia
- necrotising fasciitis
- TSS
What are the risk factors for cellulitis?
- obese
- weakened immune system
- poorly controlled diabetes / circulation problems
- chickenpox or shingles
- lymphoeddema
- IV drug use
- previous episodes of cellulitis
What are the endogenous carriers of Gp A streptococci?
- interdigital toe spaces
- vagina
- anus
What are the differential diagnosis for cellulitis?
- eczema
- lymphoedema
- allergic reaction
What is the treatment for mild/moderate cellulitis infections?
7-14 days antibiotics at home
- Phenoxymethylpenicllin (clarithromycin / clindamycin)
What is the treatment for advanced cellulitis infection?
IV benzylpenicillin (vancomycin)
What are the potential complications of cellulitis?
- bacteraemia / septicaemia
- necrotising fasciitis
- abscess
- facial cellulitis
- meningitis
