The document discusses Streptococcus pyogenes, highlighting its classification, morphology, cultural characteristics, pathogenicity, and diagnosis. It outlines the infections caused by this bacterium, including pyogenic and non-pyogenic diseases, along with their symptoms and treatments. Laboratory diagnosis methods are also presented, emphasizing the importance of specific tests for identifying infections and the recommended antibiotic therapies.

1. DEPARTMENT OF MICROBIOLOGY
VIVEKANANDHA ARTS AND SCIENCE COLLEGE FOR WOMEN
SANGAKIRI
SUBJECT: MEDICAL BACTERIOLOGY
TITLE:STREPOCOCCUS PYOGENES
SUBJECT INCHARGE: SUBMITTED BY:
Dr.R.MYTHILI, POOJA MURUGAN,
HEAD OF THE DEPARTMENT, III B.sc. Microbiology ,
assistant professor, Department of Microbiology,
Department of Microbiology, Sankagiri,
Sankagiri,
D

2. CONTENT
INTRODUCTION
CLASSIFICATION
MORPHOLOGY
CULTURE CHARACTERS
BOICHEMICAL REACTION
PATHOGENICITY
RESPIRATORY INFECTION
SYMPTOMS
LAB DIAGNOSIS
TREATMENT

3. INTRODUTION
 Streptococci [or] Gram positive cocci arranged in
chains or pairs ,they are normal flora of humans and
animals .
 Some of them are human pathogens.
 The most important one are streptococcus pyogenes
causing pyogenic infection ,which are spread as
opposed to staphylococcal lesions,which are
typically , are localized.
 Cocci in Billroth [1874] ,who called them
streptococci.

4. classfication

5. MORPHOLOGY
 The individual cocci are spherical ,oval in shape [0.5µm]
 The size may be variated from cultural conditions
 E,g. Anaerobically growing streptococcus are some what
smaller
 They are arranged in chains (i-e) chains being longer in
liquid media than in solid media
 Streptococci are non motile, non-spore formers

6. CULTURAL CHARACTERS
 It is an aerobe & facultative anaerobe, growing
best at temperature of 37°C [range 22 - 42°C].
 It is exacting in nutritive requirements ,growth
occurring only in media containing fermented
carbohydrads [or ] enriched whith blood
[or]serum.
 In blood agar at 24 hrs the organisms product
small [0.5-1µm ],circular ,semi transparent,
clearheamolysis with low convex disc.
 The growth & hemolysis only promoted by
10%CO 2

7. BIOCHEMICAL REACTION
 Catalase negative
 Bile insoluble
 Fements sugars producing acid but no gas
 PYR test positive
 Hydrolyse pyrrolidonyl-beta-napthylamide (PYR)
due to presence of peptidase, the resulting
napthylamide produces a red colour upon the
addition of 0.01% cinnamaldehyde reagent
 Failure to ferment ribose

8. BLOOD AGAR
 Small (0.5-1mm),circular,semi-transparent
colonies
 Produce wide zone of β – hemolysis
 Growth and hemolysis are promoted by 5-10%
CO2
 Mucoid colonies are formed by strains that
produce large capsules

9. PATHOGENICITY
 Produces pyrogenic infection with a tendency to
spread locally, along lymphatics and through
blood stream
 Disease caused can be:
 Suppurative
 Non suppurative

10. SUPPURATIVE
RESPIRATORY INFECTIONS:
Primary size of invasion is throat causing sore
throat .
May be localized as tonsillitis or pharyngitis.
Otitis media
Mastoiditis
Quinsy
Suppurative adenitis
Meningitis (rare)

11. SKIN AND SOFT TISSUE INFECTION
 S.pyogenus causes subcutaneous infection
ranging cellutitis to necrotising fascilitis .
 Include infections of wounds or burns ,with a
predilection to produce lymphangitis and
cellutituis .
 Infection of minor abrasions may lead to fatal
septicemia.

12. a) Impetigo [pyoderma]
 Pyo-purulent and derma-skin
 Caused by higher numeberd M types S. pyrogen.
 Superficial discrete crused spot of less than one
inch in diameter seen in children .
 Lasts for 1-2 weeks and heals spontaneously
wihtout any scars .

13. b)Erysipelas
Erysipelas and ; red pella; skin
Hypersensitivity reactioen to streptococcal
antigen
Causes acute spreading lesions involving
superficial lymphatics.
Affected skin is red ,swollen ,indurared and
sharply demarcated from surrounding
healthy skin.
Rare and seen only in order patiens.

14. c)Celluties and necrotising fascilitis
 Involves deeper subcutaneous tissues
 Local inflammation and systemic sings like
ersipelas are observes

15. NON SUPPERATIVE
 After a latent period of 1-4 weeks
 Followed by rheumatic fever and acute
glomerulonephritis
 A) Rheumatic fever
 complication of S.pyogenus pharyngitis due to
specific 1M protein tyoes,
 characterized by aschoff nodules [sub
cutaneous nodule] degeneration of haert valves
 Mimics epidemiologic character of
streptococcalpharygitis.

16. SYMPTOMS
 Otitis media
 Mastoditis
 Quinsy
 Suppurative adenitis
 Skin & soft tissue infections
 wounds on burns
 Lymphangitis
 Cellulitis
 Erysipelas

17. LAB DIAGNOSIS
 Throat swab culture ;detectin of group a antigen .
 Specific nucleic acid based test.
 Elevation of anti hyalurinidase antibodies [strong
evidence]
 Specimen;
 Throat swab , pus swab or exudates are collected .
 Microscopy ;
 Gram –staining of pus can be examinated
 Presence of gram positive cocci in chain can be
indication.

18. TREATMENT
 For group A streptococcal infection is pencillinG
 The patients who are allergic to penicilin, the
drug of choice was Erthromycin , cephalexin.
 The antimicrobial drugs have no effects on
established glomerulus nephritis and Rheumatic
fever.