Simply defined topic will give you accurate information about sore throat.

1. Sore throat
Prepared By
Arpita Chandra
Medical Microbiology

2. Sore Throat
• Sore throat is essentially an acute tonsillitis and/or pharyngitis. It is
characterised by redness and oedema of mucosa, pseudo membrane
formation, and enlargement of cervical lymph nodes.
Pseudomembrane
Inflammation of tonsils

4. Causative agents
• Bacteria:-
1. Streptococcus pyogens
2. Streptococcus group C and G
3. Corynebacterium diptheriae
4. Haemophilus influenzae
5. Treponema vicentii
• Fungus
1. Candia albicans
• Virus
1. Epstein-Barr virus
2. Adenovirus
3. Coxsackie virus

5. Symptoms:-
Pain on swallowing Congested tonsils and pharynx Enlarged lymphnodes Pyrexia
• If untreated, streptococcal tonsillitis may give rise to complication such as
peritonsillar abscess, sinusitis or immune complex diseases (rheumatic fever,
glomerulonephritis)

6. Viral vs Bacterial Sore Throat
• The most common cause of a sore throat (pharyngitis) is a
viral infection, such as a cold or the flu. A sore throat caused
by a virus resolves on its own.
• Strep Throat (streptococcal infection- about 15%), less
common type of sore throat caused by bacteria, requires
treatment with antibiotics to prevent complications

7. Laboratory Diagnosis
• Specimen:-
Throat swab
• Collection:-
Two sterile Swabs should be used, one for direct microscopy and another
one for culture. These swabs should include exudate present in the throat.
• Direct microscopy:-
Gram staining and Albert staining may be used for staining the smears.

8. • Culture:-
Culture media are selected according to the organism suspected to be the
causative agent of sore throat.
Following media may be used for culture:-
-Blood agar
-Crystal violet blood agar
-loeffler’s serum slope
-Potassium tellurite blood agar
-Sabourd’s dextrose agar

10. • Identification:-
1. Colony Morphology
2. Gram Staining or Albert Staining
3. Other test for confirmation:
 For β-haemolytic streptococci
(a) Bacitracin sensitivity test for Str. Pyogens
(b) Lancefield grouping for all β-haemolytic streptococci
 For C.diptheriae
(a) Biochemical test
(b) Toxigenicity test
 Elek’s gel precipitation test
 Animal inoculation test

11.  For Candida albicans
(a) Germ tube test
(b) Carbohydrate fermentation assimilation test
• Antibiotic Sensitivity:-
All β-haemolytic group A Streptococci are sensitive to penicillin G, and
most are sensitive to erythromycin.
C.diptheriae is sensitive to penicillin

12. COVID-19
• If you have COVID, Its more common to have other symptoms in
addition to a sore throat.
“Only about 5-10% of COVID -19 patients will have an isolated
sore throat. Usually, they will have a touch of fever. Loss of taste
and smell and difficulty breathing.”

13. Thank
you