2. Scientific classification
Domain:Bacteria
Kingdom:Eubacteria
Phylum:Proteobacteria
Class:Gammaproteobacteria
Order:Pasteurellales
Family:Pasteurellaceae
Genus:Haemophilus
Species:H. influenzae

3. Medical important species
 Haemophilus influenzae
 Haemophilus aegyptius
 Haemophilus ducreyi

4. Normal habitat
H.influenzae (mostly non-capsulated
strains), H. parainfluenzae and
H.aegyptius is normal flora of the upper
respiratory tract
Infections causing:
1. Pyogenic meningitis
2. Acute epiglottitis
3. Cellulitis, middle ear infection,etc

5. conjuctivitis

7. Microscopy
Small, non-motile, Gram negative rods
or coccobacili
Long thread-like form in old csf culture

8. Microscopic observation

9. Culture of H.influenzae
H.influenzae grows better in aerobically
compare to anaerobically
The optimum temperature for growth 35 –
37oC
The are X and V factor
Both represent in blood agar and permit the
culture to grow
H.influenzae and H.aegyptius need X and V
factor, H. parainfluenzae need V factor and
H.ducreyi need X factor

11. Biochemical tests
Not usually used to identify hemophilus
6 biovars of H.influenzae are recognized
based on the indole, urease and
ornithine decarboxylase (ODC) reactions
of the diff strains

12. Serology
Consist of 1 – f serotypes
Mostly causing meningitis belong to
serogroup b
Most strains that cause chronic bronchial
disease are non-capsulated
Antimicrobial sensitivity
Resistant towards chloramphenicol,
ampicilin, tetracycline, erythromycin and
cotrimoxazole
H. ducreyi is sensitive to sulphonamides
Ampicillin resistant are common

14. Staphylococcus aureus
Staphylococcus epidermidis
Staphylococcus saprophyticus

15. Scientific classification
Kingdom:Bacteria
Phylum:Firmicutes
Class:Bacilli
Order:Bacillales
Family:Staphylococcaceae
Genus:Staphylococcus

16. Introduction
 Are microbial flora of the skin, upper
respiratory tract and intestinal tract
 S.aureus usually cause abscesses,
boils, conjuctivitis, pneumonia,
septicemia, food poisoning and scalded
skin syndrome
 S. epidermidis causing bactericaemia
 S. saprophyticus causing cystitis and
acute urethritis

17. Laboratory diagnosis
Microscopy
 Non-motile
 Non capsulate
 Gram positive cocci
 Arrangement single or in pair
 Size 1 µm diameter

19. Culture
 Grow well in aerobically and also in
present of carbon dioxide
 Temperature between 10 – 420C,
optimum temperature are between 35 -
370C

20. S.aureus
Produce yellow to cream in blood and
chocolate agar (heated agar)
Occationally produce white 1-2 mm in
diameter colonies
Some strain produce beta-hemolytic when
grown aerobically
Colonies are slightly raised and easily
emulsified on a slide
Non- lactose fermenter in MacConkey agar
Mannitol salt agar is a useful differential
and selective agar to identify S.aureus

21. On blood agar

22. S.epidermidis
Colonyis white
Non hemolytic in blood agar
S. saprophyticus
Maybe white or yellow
There are non-hemolytic in BA
Not grow anaerobically
No growth in MacConkey agar

23. Biochemical reactions
S.aureus
DNAse test will be positive for S.aureus but
negative in other species
Catalase test will be positive in all
staphylococcus but negative in all
streptococcus
S. epidermidis and S. saprophyticus
Coagulase negative
DNAse negative
Catalase positive

24. Antimicrobial sensitivity
Erythromycin
Clindamysin
Fucidin
Vancomycin
Many strains of S.aureus are penicillin-
resistant
S.epidermidis are more resistant than
S.aureus to antibiotics
S. saprophyticus less resistant to antibiotics
than S.aureus and S.epidermidis

26. Streptococcus pyogenes
Streptococcus agalactiae
Enterococci

27. Lecture content
 Basic characteristics
 Classification
 Grouping of species
 Pathogenesis
 Lab diagnosis

28. Scientific classification
 Kingdom – Bacteria
 Phylum - Firmicutes
 Class – Bacili
 Order – Lactobacillales
 Family – Streptococcaceae
 Genus - Streptococcus
 Species – 22 sp.

29. Basic characteristics
 Gram-positive
 Lactic acid bacteria group
 Spherical
 Grow in chain (twisted) or pairs
 Mostly are facultative anaerobes

30. Habitat
 Available in food such as
Emmentaler (Swiss) cheese
 Normal flora of the mouth,
skin, intestine and upper
respiratory tract of humans

32. Classification

33. Alpha hemolysis
Surrounded by an area of partial
haemolysis
Green-brown colour (reduced
haemoglobin)
Consist of pneumococci and
viridans group( alpha hemolytic
and no Lancerfield antigens

35. Pathogenicity
S.pyogenes (Group A)
 Acute sore throat
 Scarlet fever
 Ear infections
 Peurperal sepsis
 Septicemia and occasionally endocarditis
 Skin infection such as celulitis and impetigo

36. Post-streptococcal disease
From the implication of pathogenesis, it will
leads to a serious stage of diseases:
 Acute glomerulonephritis
 Rheumatic fever

37. Enzymes & toxin production
By S. pyogenes
 Streptolysin O
 Streptolysin S
 Streptokinase (cause fibrinolysis)
 Hyarulonidase
 DNAses
 DPNAse
 Erythrogenic toxin

38. Other species
S.Agalactiae (Group B)
 Neonatal septicaemia, pneumoniae, meningitis
 Septic abortion and peurperal sepsis
Enterococci (Group D)
 Urinary tract infection
 Infections of ulcer and wounds
 Endocarditis and meningitis
Viridans
 Endocarditis
 Dental caries
 Brain abscess

40. Microscopy
 Gram positive (purple)
 Non-motile
 Long chains
 Sometimes in pair

41. Culture
 Aerobically and anaerobically
 Temperature between (22 – 42o C)
 And enterococci are between (15 – 45o C)
 On BA, colony usually less than 1 mm in
diameter
 Grey – white or colourless
 Dry / shiny, irregular outline
 Most of the pathogenic streptococcus
producing hemolysins

42. S. pyogenes
 Produce beta hemolysis
 Sensitive to bacitracin (can’t rely 100% to
it, coz not only group A sensitive to it) but
for viridans it is resistance towards
bacitracin
 A selective BA containing crystal violet was
suggested
 Does not grow in MacConkey agar

43. S.agalactiae
 Optochin resistant but S.pneumoniae is
sensitive
 Beta hemolysis in BA
 In serum starch agar, it produces orange
pigment

44. Biochemical test
Species Catalase Bacitracin Optochin Litmus CAMP
Milk
S.pyogenes - + - - -
S. agalactiae - - - - +
Enterococci - - - + -
Viridans - - - - -
streptococci
Pneumococci - - + - -