This document discusses acute rheumatic fever, which can develop as a complication of untreated streptococcal infections like strep throat. It is caused by Streptococcus pyogenes bacteria. The document covers the classification, morphology, culture characteristics and pathogenesis of S. pyogenes. It also discusses the signs and symptoms of acute rheumatic fever, laboratory diagnosis including antigen and antibody tests, and imaging studies used to diagnose rheumatic heart disease. Rheumatic fever remains an important cause of acquired heart disease in developing countries.

1. PREPARED BY :
 Anil Gurung
 Ashmita Thapa
 Bishan Shrestha
 Prashamsa Poudel
 Samikshya Bhattarai
 Shreelabi Timila
 Sushma Adhikari
 Susmita Mandal
CORELATION SEMINAR
On
Acute Rheumatic Fever
DEPARTMENT OF MICROBIOLOGY

2. CONTENTS
INTRODUCTION
CAUSES
CLASSIFICATION OF STREPTOCOCCUS
STREPTOCOCCUS PYOGENS:
-MORPHOLOGY
-CULTURAL CHARACTERISTICS
-PATHOPHYSIOLOGY
-LABORATORY DIAGNOSIS

3. INTRODUCTION
•RHEUMATIC FEVER
Rheumatic fever is an inflammatory disease that
can develop as a complication of inadequately
treated streptococcal sore throat or scarlet fever
which can lead to RHEUMATIC HEART
DISEASE.

4. CAUSES
Streptococcus pyogens (β-hemolytic streptococcus)
- They Exhibit a wide zone (2-4 mm wide) of complete
haemolysis with the presence of enzyme Streptolysin.
(RBC)

5. OTHERS FACTORS INCLUDES:
Streptococcal sore throat
Rheumatogenic potential
Recent virus (Coxsackie B-4) has been suggested as a
causative agent.

6. CLASSIFICATION OF
STREPTOCOCCUS

8. STREPTOCOCCUS
PYOGENS

9. MORPHOLOGY
 A spherical bacterium (cocci) that appears in
chain-like formations.
Gram-positive bacteria
Facultative anaerobes
Capsulated
Non motile
Non sporing

10. ANTIGENIC STRUCTURE

11. CULTURAL CHARACTERISTICS
They are aerobic and
facultative anaerobes.
They grow best at 37˚ Celsius
Growth is poor on solid media or broth
Grow well in media containing blood and sugar and 10%
CO2 in environment promotes growth and hemolysis

12. ALPHA HEMOLYSIS ON BLOOD AGAR

13. BETA HEMOLYSIS ON BLOOD AGAR

14. PATHOPHYSIOLOGY

15. Mode of transmission –inhalation/ingestion of bacteria
Entry of bacteria
Pharyngitis by Group A β-hemolytic streptococcus
M1 protein of streptococcus pyogens is released in blood circulation
97 % pharyngitis is cured ,but ~3 % there is development of
antibodies against M1 protein by host immune system
M1 protein has molecular similarity with glycoprotein antigen of
human cell membrane thus antibodies cross react with them and
affect heart ,joints and brain
RHEUMATIC FEVER
Recurrent of bacteria and reactivation of immune system
Progressive damage

16. Clinical symptoms
-Primarily acute infections of respiratory tract and
skin are seen.
-Sore throat (acute tonsilitis and/or pharyngitis) is
most common.

17. Jones criteria:-
1. Polyarthritis

18. 2. Carditis
3. Subcutaneous nodules

19. 4. Sydenham’s syndrome

20. 5. Erythema marginatum

21. LAB DIAGNOSIS

22. SPECIMEN
-Collected from the site of lesion such as:-
1.Swab
2.Pus
3. Blood
-Collection of specimen depends on the nature of
infection such as swab taken from throat , vagina or
purulent lesion of patients and throat and nose of
suspected carriers.

23. MICROSCOPY
The information may be obtained by an examination of
gram stain film from pus.
The presence of gram positive cocci in chain is indicative of
streptococcal infection .

24. CULTURE
 Specimen:
- SPIKE’S TRANSPORT MEDIUM (Blood agar
containing 1 in 1,000,000 crystal violet and 1 in
16000 sodium azide.)
- Blood agar medium and incubated at 37 C for
overnight .
 Haemolysis develops better under anaerobic condition or
under 5-10 % CO2 .
 Sheep blood agar is preferable as human blood may
contain inhibitors.
 The bacterial colonies are small typically dry and
surrounded by beta haemolysis .

25.  Serological test:-
1. ANTIBODY TITRE TEST
2. ELISA
3. AGGLUTINATION TEST
4. ERYTHROCYTE SEDIMENTATION
RATE (ESR)
5. C-REACTIVE PROTEIN LEVEL
6. HEART REACTIVE ANTIBODY
7. RAPID DETECTION FOR B CELL
MARKER

26. ANTISTREPTOLYSIN O TEST
It is used to detect streptococcal antibodies directed against
streptococcal lysin O .
 ASO test is done by serological methods like LATEX
AGGLUTINATION OR SLIDE AGGLUTINATION.

27. PROCEDURE
1.Bring all reagents and specimens to room temperature.
2.Place one drop (50 µl) of the positive control and 50 µl of the patient
serum into separate circles on the glass slide.
3.Shake the ASO latex reagent gently and add one drop (45 µl) on each
circle next to the sample to be tested and controlled.
4.Mix well using disposable stirrer spreading the mixture over the whole
test area and tilt the slide gently. Agitate for about 2 minutes with rotator
or by hand and observe for the presence or abscence of agglutination...

28. RESULT AND INTERPRETATION
Negative result:
No agglutination of the latex particles suspension
within two minutes.
Positive result:
An agglutination of the latex particles suspension will
occur within two minutes, indicating an ASO level of
more than 200 IU/ml.

29. ACUTE PHASE REACTANT , ERTHROCYTE
SEDEMENTATION RATE AND C-REACTIVE
PROTEIN
 They are usually elevated at the onset of ARF and serve as
a manifestation in the Jones criteria.
 These test are non specific but they maybe useful in
monitoring disease activity.

30. HEART REACTIVE ANTIBODY
Tropomyosin is elevated in persons with acute rheumatic
fever

31. RAPID DETECTION FOR B CELL MARKER
This immunofluorescence technique for identifying the B-
cell marker D8/17 is positive in 90% of patients with
rheumatic fever and may be useful for identifying patients
who are at risk of developing rheumatic fever

32. Imaging Studies
A. Chest radiography
Chest radiography can reveal cardiomegaly and CHF in
patient with carditis

33. • B. ELECTROCARDIOGRAM (ECG)
 ECG may demonstrate valvular regurgitant lesions
in patient with ARF who do not have clinical
manifestation of carditis.

34. CONCLUSION
RHEUMATIC FEVER is still the most common cause of
acquired heart disease in many developing countries.
The precise pathogenetic mechanism have never been
properly defined.
However it has been hypothesized that on exposure to
group A streptococci during infection ANTIGENIC
MIMICRY leads to autoimmune like reaction within the
human host and results in valvulitis , ultimately leading to
rheumatic valvular heart disease.

35. REFERENCES
 LIPPINCOTT’S ILLUSTRATED REVIEWS
 A TEXT BOOK OF MICROBIOLOGY -
CHAKRABORTY