Streptococcus pneumoniae, commonly known as pneumococcus, is a gram-positive bacterium that is a major cause of pneumonia, meningitis, and sepsis. It was first observed in 1881 and its relationship to pneumonia was established in 1886. It is a lancet-shaped diplococcus that appears in pairs and is encapsulated. Pneumococcus can be identified through its morphology, culture characteristics, and reactions like optochin sensitivity and bile solubility. It is a human pathogen that can cause diseases like pneumonia, meningitis, and sepsis. Vaccines like PCV7 for children and PPV23 for adults help prevent pneumococcal infections.

1. Streptococcus pneumoniae
By:- Dr.Manish Tiwari
Department of microbiology
Mail id :
mprabhat111@gmail.com
Mob No:8979352824

2. INTRODUCTION:
 Common name Pneumococcus.
 Formerly known as Diplococcus
pneumoniae.
 Has been reclassified as S. pneumoniae
because of its genetic relatedness to
Streptococcus spp.
 Normal inhabitants of the upper respiratory
tract of human beings.

3.  Streptococus pneumoniae were first
noticed in 1881 by Pasteur and Sternberg.
 But the relationship between the organism
and pneumonia was established by Frenkel
in 1886.
 It is different from other Streptococci chiefly
in its morphology.

4. MORPHOLOGY:
 Gram positive, small(1μm),
slightly elongated cocci,
with one end broad &
other end pointed:
Flame shaped or
lanceolate appearance.
 Occur in pairs, with the
broad ends opposing each
other.
 They are capsulated & the
capsule encloses each
pair.
 Nonmotile & nonsporing.

5. CULTURE & CULTURAL CHARACTERISTICS:
 They grow only in enriched media.
 They are aerobes & facultative anaerobes.
 The optimum temperature being 37ºC & pH
7.8.
 Growth is improved by 5-10% CO2.

6. Continue…………
1. SIZE: 0.5 to 1 mm
2. SHAPE: pin point
3. SURFACE: Smooth
4. EDGES: undulate
5. ELEVATION: Convex
6. COLOR: Greenish
7. CONSISTANCY: Mucoid

7. Continue…..
8. CHANGE IN MEDIA: α-hemolysis
9. ODOUR: putrid
10. OPACITY: Translucent
11. EMULSIFICATION: Easily emulsify

8. Culture Media : Blood agar
Colony morphology: On blood agar, after
incubation for 18 hours, the colonies are small,
dome shaped & glistening, with an area of
α-haemolysis.
On further incubation the colonies
become flat with raised edges & central
umbonation called as Draughtsman colony or
Carrom coin appearance.

9.  α -Haemolysis  β- Haemolysis

10. Resistance
 Streptococcus pneumoniae are delicate
organisms.
 It is destroyed by heat and antiseptics at 52
degree centigrade (thermal death point).
 But in culture media its die on pronlonged
incubation because excess accumulation of
toxic peroxides.
 They are sensitive to most antibiotics B-
lactame

11. BIOCHEMICAL REACTIONS:
1) Catalase test: Negative.
2) Bile solubility test: Positive.
3) It ferments inulin.

12. Catalase test
Bile solubility test

13. Antigenic structure:
1. Capsular polysaccharide:
 It is the most important antigen & type specific.
 Since it diffuses into infective tissue & culture
medium it is called as specific soluble
substance(SSS).
 Pneumococci are classified into types based on
the nature of capsular polysaccharide & more than
90 serotypes are recognised & named 1,2,3…...

14. 2. M protein: It is not associated with virulence.
3. ‘C’ Carbohydrate antigen:
- It is present in all pneumococci so species specific.
- An abnormal protein(β-globulin) that precipitates
with ‘C’ carbohydrate antigen of pneumococci,
appears in the acute phase sera of cases of
pneumonia but disappears during convalescence. It
also detected in sera of patients with some other
illness. This is known as the C-Reactive
Protein(CRP). It is an ‘acute phase’ substance,
produced in hepatocytes. Its production is stimulated
by bacterial infections, inflammation, malignancies &

15. Virulence factors:
1. Capsule: It is antiphagocytic because of its
acidic and hydrophilic properties, so its
protect the coccid from phagocytosis.
2. Pneumolysin: It is a membrane damaging
toxin has cytotoxic and complement
activating properties.
3. Autolysin: Its released by bacterial
component in the infected tissue .

16. Antigenic structure & virulence factors of S.pneumoniae

17. PATHOGENICITY:
Source of infection:
i) Endogenous- from the colonized area.
ii) Exogenous- patients or carriers.
Mode of infection: By inhalation.

18. Mechanism of Pathogenesis:
Entry of pneumococci into nasopharynx
Colonization of nasopharynx
May cause infection of the middle ear, paranasal
sinuses & respiratory tract by direct spread
Infection of meninges can also occur, by contiguity or
through blood
Enters blood causing bacteremia, which may also
lead to disseminated infections as in the heart,
peritoneum or joint

19. Disease:
1. Otitis media & sinusitis
2. Pneumonia
a. Lobar pneumonia
b. Bronchopneumonia
3. Tracheobronchitis
4. Meningitis
5. Other infections- empyema, pericarditis,
conjunctivitis, suppurative arthritis & peritonitis.

20. LABORATORY DIAGNOSIS:
Specimens to be collected:
 Sputum
 CSF
 Blood
 Synovial fluid
 In children laryngeal swab can be taken if
sputum can not be collected.

21. Laboratory diagnosis:
1.Direct microscopy:
Gram stained
smears reveals
Gram positive
lanceolate
diplococci with
numerous pus cells.

22. 2. Quellung( capsular swelling ) reaction:
 It is described by Neufeld.
 On a slide the sputum is mixed with type
specific antiserum against capsular antigen &
a loopful of methylene blue solution. The
capsule becomes swollen & refractile.

23. 3. Antigen detection: Capsular polysaccharide
antigen in blood, CSF & urine can detected by
 Passive latex agglutination,
 Counter immunoelectrophoresis,

24. 4. Culture:
a) Media used:
b) Colony morphology:
c) Gram’s smear:
Smears are examined
from the culture plate
and reveals Gram
positive lanceolate
shaped diplococci.

25. d) Capsular swelling reaction: Positive.
It is done by mixing the suspension of
colonies from the culture plate and a loopful
of type specific antiserum & a drop of
methylene blue solution on a slide.
e) Biochemical reactions:

26. f) Optochin sensitivity: Sensitive.

27. 5. Animal inoculation: From specimens where
organisms are expected to be scanty,
isolation may be obtained by intraperitoneal
inoculation in mice.
6. Serology: Antibodies can be demonstrated
by agglutination & precipitation test.
7.Biomarker: CRP testing by passive
agglutination using latex particles coated
with anti CRP antibody.
8.Molecular method : PCR based method
have much potential where the patient has
taken antibiotics.

28. TREATMENT:
 For Penicillin sensitive strains Penicillin is
drug of choice for serious cases & Amoxycillin
for milder ones.
 For Penicillin resistant strains a third
generation cephalosporin is indicated.
 Vancomycin is to be reserved for life
threatening illness with highly resistant
strains.

29. EPIDEMIOLOGY:
 Pneumococci occur in the throat of
approximately half the population sampled at
the time.
 Spreading is facilitated by over crowding.
 Disease results only when the host resistance
is lowered by factors such as respiratory viral
infections, pulmonary congestion,
malnutrition, immunodeficiency, stress &
alcoholism.

30. PROPHYLAXIS: A polyvalent vaccine
containing the capsular antigens of 23 most
prevalent serotypes is being used.
Vaccine:
Name:
Route:
Dose :
Indications:
Advantage:
Disadvantage:
Brand names:

31. Continue………
 Vaccine:-vaccine is antigenic substance
prepared from the causative agent of
disease which used to provide immunity
against one or several disease.
 Name:- 1. PCV 7 and 2.PPV 23
 Route:- both vaccine are given by
intramuscular or subcutaneous

32. 1. Pneumococcal conjugate vaccine
 Recently a new vaccine has been
developed that is suitable for infants/
toddlers is called PCV7
 It contains 7 selected polysaccharide bound
to protein carrier and induce T – cell
independent immune response.
 This vaccine is very effective in preventing
pneumococcal pneumonia and meningitis.
 This vaccine stimulates only mature B –cell
but not T –cell.

33. Doses
 0.5 ml dose & it contain 0.125mg. of
aluminum, a metal that is neurotoxic.
 The primary series of PCV-7 consist of 3
intramuscular dose administered to infants
at 2 ,4 and 6 month of the age
 Booster dose administered after 12 month of
the age may improve the immune response.
Indication
Redness, swelling, pain, fever, loss of
appetite, headache, chills etc.

34. 2.Pure polysaccharide vaccine
 It is non conjugate vaccine and contains
capsular antigen of 23 serotypes.
 It is effective against infection of Pneumococcal
bacteria for adults over 65 yrs of the age. Childre
under 2 yrs of the age.
 This vaccine contains 25 microgram of the
purified capsular polysaccharide from each 23
serotypes
 Immunity is long lasting and vaccine gives 80-

35. Doses
 A single dose of 0.5 ml can be administered
by intramuscular or subcutaneous dose.
Indication
Redness, pain, fever, muscle ache. etc

36. Drawbacks of this vaccine
 Pure polysaccharide vaccine that provoke a
B-cell antibody response but its T- cell
independent antigen, So it’s a protective
immune response is not seen in children
less than 2 years.
 Pneumococcal Polysaccharide vaccine
include its inability to affect Nasopharyngeal
Pneumococcal carriage and therefore the
spread of organism from person to person.

37. Advantage of Vaccine
 It prevent the pneumococcal disease.
 Reduction of disease transmission.
 Reduction of Antibiotic Resistance
 It provide immunity against pneumococcal
infection.
Disadvantage
 It Harmful effect for pregnant women

38. Brand Names of the vaccine
1. Pure Polysaccharide vaccine there brands
name is : PNEUMOVAX 23.
2. Pneumococcal conjugate vaccine there
brands name is : PREVNAR 7.

39. Difference between S.pneumoniae and
S.viridans
S.Pneumoniae Viridans
morphology Capsulated,lanceolate
diplococci
Non capsulated, oval or
round cells in chain
Quellung test positive negative
Colony on blood agar Initially dome shaped later
draughtsman colonies
Dome shaped
Growth in liquid media Uniform turbidity Granular turbidity, powdery
deposit
Bile solubility positive negative
Inulin fermentation positive negative
Optochin sensitivity positive negative
Intra peritoneal inoculaton
in mice
Fatal infection Non-pathogenic

40. MCQ
1. The process of converting capsular
pneumococci into virulent organism is
called..
(A) Transduction (B) Conjugation
(C)Transformation (D) Non of these

41. 2 .Inulin is ………….
(A) protein (B) Vitamin
(C) carbohydrate (D) aminoacid

42. 3. All Pathogenic bacteria in microbiology
measure between ,
(A) 1-3μm (B) 3-5μm
(C) 5-10μm (D) >20μm

43. 4. Carrom coin apperance of pneumococci is
due to..
(A) Autolysin (B) Hemolysin
(C) Leucocidin (D) tetanolysin

44. 5.( ………….) test is used to identify the
serotype of pneumococci.
(A) inulin test (B) Quellung test
(C) Optochin Sensitivity test (D) catalase
test

45. 6. which of the following statement is true
about S.pneumoniae
(A) Gram negative cocci in pairs
(B) About 2 μm in diameter
(C) It is Gram positive cocci in pairs
(D) It is Gram positive cocci in chain

46. 7. Which of the following statement is true
about pneumococci..
(A) Quellung test negative
(B) inulin fermentation test positive
(C) Katalase test positive
(D) Bile solubility test negative

47. 8. which of the following statement is false
about pneumococci..
(A) It is motile
(B) Non motile
(C)Capsulated
(D) Non sporing

48. 9. which of the following statement is true
about PCV7 pneumococcus vaccine..
(A) it suitable for all adults
(B) it suitable for infants & toddlers
(C) It contain 13 serotype of antigen
(D) Its suitable for 20 to 30 years old man

49. 10. which of the following statement is false
about PCV7 pneumococcus vaccine..
(A) T – cell dependent
(B) T – cell independent
(C) it suitable for infants
(D) Its contain 7 serotype of antigen

50. 11. which of the following statement is true
about PPV23 vaccine.
(A) provide immunity for long lived
(B) for short lived
(C) it suitable for only adult
(D) Its suitable for infants

51. Reference…..
 Text book of Ananthanarayan & Paniker’s
Text book of Koneman’s
Text book of Mackie & McCartney
Text book of K.Park’s(Community Medicine)