Streptococcus pyogenes Flashcards
Is streptococci a gram positive of gram negative cocci?
Gram positive
Name some of the virulence factors for streptococcus pyogenes.
- Hyaluronic acid capsule
- M protein
- Hyaluronidase
In which age group is streptococcal pharyngitis most common (caused by streptococcus pyogenes).
5-15yrs
How is streptococcus pyogenes spread?
Droplet spread
(association with overcrowing)
What are the clinical features of streptococcal pharyngitis?
- Abrupt onset sore throat
- Malaise
- Fever
- Headache
- Lymphoid hyperplasia
- Tonsillopharyngeal exudates
- Throat swab will show GROUP A STREP
Name some complications of streptococcal pharyngitis.
- Scarlet fever
- Retropharyngeal abscess
- Peritonsillar abscess
- Sinusitis
- Menigitis
- Acute rheumatic fever
What is scarlet fever?
- Due to streptococcal pyrogenic exotoxin starin of S.pyogenes
- Local/haematogenous spread
- High fever, sepsis, arthiritis, jaundice
What is acute rheumatic fever?
Inflammation of heart, joints, CNS
Name 4 skin infections caused by streptococcus pyogenes.
- Impetigo
- Erysipelas
- Cellulitis
- Necrotising fasciitis
In what population is impetigo found?
Children- 2-5 yrs
Initial skin colonisation then intradermal innoculation
Which area is affected by erysipelas?
Dermis infection w./ lymphatic involvement
Face/lower limbs
Facial lesions
Which area is infected by necrotising fasciitis?
Deeper subcutaneous tissues and fascia
Rapid+ extensive necrosis
Usually secondary to skin break
Severe pain, high fever, high mortality
What are the 4 pathologies causing streptococcal toxic shock syndrome?
- Deep tissues infection with Strep pyogenes
- Bacteraemia
- Vascular collapse
- Organ failure
What is shown in the following gram stain?
Strep pyogenes
