Your SlideShare is downloading. ×
Lecture 3 Streptococcus pyogenes
Upcoming SlideShare
Loading in...5
×

Thanks for flagging this SlideShare!

Oops! An error has occurred.

×

Introducing the official SlideShare app

Stunning, full-screen experience for iPhone and Android

Text the download link to your phone

Standard text messaging rates apply

Lecture 3 Streptococcus pyogenes

791
views

Published on

Published in: Health & Medicine

0 Comments
2 Likes
Statistics
Notes
  • Be the first to comment

No Downloads
Views
Total Views
791
On Slideshare
0
From Embeds
0
Number of Embeds
0
Actions
Shares
0
Downloads
96
Comments
0
Likes
2
Embeds 0
No embeds

Report content
Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

Cancel
No notes for slide

Transcript

  • 1. ‫بسم ا الرحمن الرحيم‬ GENUS: STREPTOCOCCUS Prof. Khalifa Sifaw Ghenghesh
  • 2. The Majority are Facultative Anaerobes. G +v Cocci Arranged in Chains, Some are Capsulated. Catalase: On Blood Agar: 1. β-Haemolytic Streptococci (Strep. pyogenes) 2. α-Haemolytic Streptococci (Strep. pneumoniae) 3. Non-Haemolytic Streptococci (Strep. Faecalis = Enterococcus faecalis).
  • 3. A photomicrograph of Streptococcus spp.
  • 4. Streptococcus pyogenes Lancefield Grouping > Haemolytic Streptococci by Serology > > Groups A-H & K-V. Group A = Strep. Pyogenes Griffith Types Lancefield Group A > by Specific Sera >> Types M, T, & R. Type M > 60 Serotypes > Type 1, Type 2, Etc..
  • 5. VIRULENCE FACTORS A. Structural Components:> M-Protein > B. Extraceluular Products: Erythrogenic Toxins: > In Experimental Animals: Pyrogenicity, Cytotoxicity, Immunosuppresion, etc. Streptolysin O and Streptolysin S: Lysis RBCs. Streptokinase (Fibrinolysin): > Prevents the formation of an effective fibrin barrier Deoxyribonucleases (DNases): Hyalorunidase:
  • 6. CLINICAL INFECTIONS Acute Sore Throat Impetigo Erysipelas Scarlet Fever Rheumatic Fever Acute Glomerulonephritis.
  • 7. Inflammation of the oropharynx and petechiae, or small red spots on the soft palate caused by Streptococcus group A
  • 8. LABORATORY DIAGNOSIS: A. By Direct Isolation & Identification: 1. Specimens: i. Throat Swabs > Patients with Sore Throat (Tonsillitis and /or Pharyngitis). ii. Throat and Nasal Swabs > Carriers (Outbreaks of Sore Throat or Scarlet Fever).
  • 9. 2. Culture: > 2 Blood agar plates > If β - Haemolytic > Bacitracin sensitivity test > Sensitive >> Group A Streptococci. 3. Confirmation: > Lancefield's Serogrouping (Commercial Kits).
  • 10. B. By Examination of Patient's Sera for Rising Titre of Antibodies to Streptococcal Antigens (e.g. RF or AGN): 1. Specimens: > Two Serum Samples are Collected in the Acute and Convalescent Stages. 2. Test: > The Antistreptolysin-O (ASO) Test. TREATMENT: S. Pyogenes > Penicillin G or Erythromycin
  • 11. GROUP B STREPTOCOCCI Strep. agalactiae > A major Streptococcal Pathogen in Neonates and the Young Infants. 1. Early-Onset Infection:> Septicaemia 2. Late-Onset Infection: > Purulent Meningitis > Infection in Adults: GROUP D STREPTOCOCCI: Enterococcus faecalis