1. Individual bacteriology

2. Chapter 14 Coccus

3. Main contents Biological characterization Pathogenesis and immunity
Laboratory diagnosis
Treatment and control

4. Outline 5 pathogenic cocci G+ cocci: Staphylococcus aureus
Streptococcus pyogenes
Streptococcus pneumoniae
G- cocci: Neisseria meningitidis
Neisseria gonorrhea
※Biological characteristics
※Pathogenicity

5. Section 1 Staphylococcus
“staphyline”
grape-like

6. Staphylococcus At least 30 species S.aureus: most virulent species.
S.epidermidis: opportunistic pathogen.
S.saprophyticus: rarely cause human diseases.

7. Biological characteristics
Shape and structure
Size: about 1.0 m in diameter
Shape: round
Arrangement: grape-like
Structure: no flagella,
can not form spores
Staining: G+

8. Biological characteristics
Cultivation
Requirements:
grow well on basic media
facultative anaerobes or
aerobes
37℃
pH: 7.4

9. Biological characteristics
Growth properties
liposoluble pigments
some strains of S.aureus form complete hemolysis (-hemolysis)
S.aureus and S.epidermidis

10. Biological characteristics
Biochemical reactions
Catalase test “+”
Staphylococci: “+”
Streptococci: “-”
Mannitol Fermentation “+”
S. aureus: “+”;
S.epidermidis & S.saprophyticus: “-”;

11. Biological characteristics
Antigenic composition
Carbohydrate antigens:
capsules & teichoic acid
Protein antigen: SPA
Staphylococcal protein A
Characteristics:
nonspecific bind to
the Fc fragment of IgG

12. SPA(staphylococcal protein A)
IgG
Fc receptor
Phagocyte
BACTERIUM
Fab Fc

13. Biological characteristics
Function:
virulence factor
Anti-phagocytosis;
damage platelet;
induce hypersensitivity and inflammation;
coagglutination test
SPA-coated S.aureus is used as Ab carriers

14. SPA (staphylococcal protein A )
S.aureus Ab

15. Thermostable nuclease
Classification
Based on the pigments and chemical reactions
Properties
S. aureus
S. epidermidis
S. sarprophyticus
Pigment
Golden yellow
White
Citrine
Coagulase + － －
Mannitol + － －
Thermostable nuclease + － －
α-hemolysin + － －
SPA + － －
Pathogenicity
strong
Weak -

16. Classification Based on coagulase Phage typing
Coagulase” +”: e.g., S. aureus
Coagulase” -”: e.g., S. epidermidis & S. saprophyticus
Phage typing
S. aureus: 4 phage groups, 23 phage types.
group Ⅰ: TSST-1-producing strains
group Ⅱ: exfoliative toxin-producing strains
group Ⅲ: enterotoxin-producing strains
----is of epidemiological value

17. Resistance to environment
Dry
Heat
high concentration of salt (10-15% NaCl)
Sensitivity:
basic dyes (crystal violet)
several antibiotics (penicillin, vancomycin)
MRSA (methicillin resistance S.aureus)

18. Pathogenicity (S.aureus)
Virulence factors
Invasiveness
Surface structure
SPA, capsules
Enzyme
Toxin---exotoxin
Hemolysins
Leukocidin
Staphylococcal enterotoxin
TSST-1
Exfoliative toxin

19. Enzyme
Coagulase:
An enzyme that converts fibrinogen in citrated human or rabbit plasma into fibrin causing the coagulation of blood.
Classification:
Free coagulase
Bound coagulase
Roles
to inhibit the phagocytosis of macrophages and damage of bactericidal substances in body by coating the bacteria with fibrin.
Localized infection

20. fibrin-coated staphylococci

21. Free coagulase
tube coagulase test

22. Bound coagulase
slide coagulase test

23. Other enzymes Staphylokinase: plasminogen---plasmin
Heat stable nuclease:degrade DNA and RNA
Hyaluronidase (spreading factor)
lipase

24. Exotoxin Hemolysins----staphylolysin
Roles: damage membrane permeability;
cytotoxic effects on RBC and tissue cells
Five kinds:-Lysin (main pathogenic substance)
-Lysin
-Lysin
-Lysin
-Lysin
S.Aureus in blood agar

25. leukocidin Increasing membrance permeability
Cytotoxic effects on neutrophil and macrophage
antiphagocytosis

26. Staphylococcal enterotoxin
1/2 strains of S.aureus produce it.
Produced by S.aureus strains of phage group Ⅲ
Chemical and physical characteristics:
protein
Heat stable (100℃, 30 min)
Resistant to proteolytic enzymes of GI tract
multiple types: A-E，G-I , K-M
superantigen
Role: stimulate vomiting-control center and cause a food poisoning characterized by vomiting.

27. Toxic shock syndrome toxin-1 (TSST-1)
Produced by S.aureus strains of phage group Ⅰ
superantigen
Role:
induce fever, shock, hypotension, desquamative skin rash, multisystem involvement;
enhance the host susceptibility to endotoxin

28. Exfoliative toxin---epidemolytic toxin
strains of phage-group Ⅱ
Superantigen
Role:
Split desmosomes in stratum granulosum layer of epidermis
blister of skin
associated with SSSS
SSSS: staphylococcal scalded skin syndrome

29. Pathogenicity Disease Invasive infection/pyogenic infection
local infection: folliculitis; boil; carbuncle; impetigo;suppuration of wound
(Lesion is limited in local area and pus is thick and yellow)
organ infection: pneumonia; meningitis,endocarditis
Systemic infection: Septicemia; pyemia
Toxin-associated diseases

30. hair folliculitis
boil

31. folliculitis
impetigo
carbuncle
boil

32. Pathogenicity Toxin-associated diseases Food poisoning (enterotoxin)
TSS (Toxic shock syndrome)
SSSS (staphylococcal scalded skin syndrome)

33. Staphylococcal scalded skin syndrome (SSSS)
Most often occurs in infants
and young children

34. Diseases caused by coagulase negative staphylococci(CNS)
S.epidermidis
urinary tract infection
Bacterial endocarditis
Septicemia
Wound infection
S.saprophyticus
Community-acquired urinary tract infection

35. Laboratory diagnosis Specimen Direct smear and Gram stain
Isolation and identification
Primary criterions:
coagulase test,
thermostable nuclease
gold yellow pigmentation
-hemolysis
mannitol fermentation
Enterotoxin test (animal test)
Antibiotic susceptibility tests

36. pathogenic cocci 3 Genus G+ cocci: Staphylococcus G- cocci: Neisseria
S. aureus
Streptococcus
S. pyogenes
S. pneumoniae
G- cocci: Neisseria
N. meningitidis
N. gonorrhea

37. Section 2 Streptococcus

38. Biological characteristics
Morphology & cultivation properties
Spherical, G+, arranged
in chains, microcapsule,
pili-like structure
no flagella,
can not form spore
Nutritive requirement: high
“flesh-eating bacteria”

39. On blood agar:
tiny colony (1-2mm)
different hemolysis
Most are facultative anaerobe,some are obligate anaerobe
catalase negative---distinguish streptococcus and staphylococcus

40. Biological characteristics
Classification
Hemolytic activity
-hemolytic strep.
Incomplete hemolysis
Opportunistic pathogens
e.g., S.pneumoniae, S.viridans
-hemolytic strep.
Complete hemolysis()
Major human pathogens
e.g., S. pyogenes
-streptococcus
No hemolysis,
No pathogenicity
e.g., enterococci.

41. Biological characteristics
Antigenic structure
Carbohydrate antigen
group-specific antigen
20 groups (A~H, K~V)
Group A-main human pathogens
Protein antigen
type-specific antigen
M, R, T protein
Group A >80 types
Cell wall
Streptococcus
capsule
protein
Polysaccharide
Peptidoglycan

42. Biological characteristics
Resistance
Heat labile: 60℃, 30 min
Antibiotics sensitivity: penicillin G ,etc.

43. Pathogenesis(group A streptococcus)
Virulence factors
Surface structures
LTA: adhere to sensitive cell
M-protein:
a.Anti-phagocytosis
b.Be associated with
rheumatic heart disease & glomerulonephritis
c.Adhere to epithelial cells
protein F：receptor of fibronectin on epithelial cell
hair
like
pili

44. S. pyogenes
lipoteichoic acid
F-protein
fibronectin
epithelial cells

45. Enzymes Pathogenesis Hyaluronidase (spreading factor)
Streptokinase (SK) ---myocadial infarction
Streptodornase (SD)

46. Pathogenesis Streptolysin (hemolysin)
Toxins---exotoxin
Streptolysin (hemolysin)
Streptococcal pyrogenic exotoxin (Erythrotoxin, scarlet fever toxin)

47. Streptolysins streptococci group A, C, and G; Destroy RBC,WBC,platelet
Classification:
Properties
Streptolysin O (SLO)
Streptolysin S (SLS) O2
oxygen-labile
oxygen-stable
Antigenicity
Strong (ASO test)
Weak
Chemical
Protein (MW60,000)
Polypeptide (28aa)

48. Anti-SLO Test
Definition: a neutralization test or indirect agglutination test between the toxin (SLO) and its specific anti-toxin (ASO) helping to diagnose of recent streptococcus infection and active rheumatic fever.
Positive standard: > 250 IU/ml
Active rheumatic fever: > 400 IU/ml

49. Erythrotoxin pyrogenic toxin /scarlet fever toxin
Strep. group A (lysogenic)
protein
Antigenicity
A,B,C serotypes
Scarlet fever and toxic shock syndrome

50. Pathogenesis Disease caused by Strep. Group A Transmission:
Respiratory tract, trauma, gastrointestinal tract
3 types of infections

51. Abscess with surrounding cellulitis
Types of infections
Abscess with surrounding cellulitis
Pyogenic infection:
Local purulent infections:
pharyngitis, tonsillitis;
puerperal fever, erysipelas, cellulitis,
impetigo;lymphangitis,lymphadenitis
Systemic infection: septicemia

52. Erysipelas
Erysipelas on
the cheek

53. Toxin-associated diseases:
scarlet fever:
Toxic shock syndrome

54. Types of infections Hypersensitivity type II & III
Hypersensitive disease
Acute glomerulonephritis
edema, hypertension, hematuria and proteinuria
Rheumatic fever:
involve: heart, joints, subcutaneous tissue, and CNS;
fever, migratory polyarthritis, carditis
Hypersensitivity type II & III

55. Prevention and treatment
Treat the pharyngitis and tonsillitis in time
Antibiotics: penicillin G for the first choice

56. Section 3 Streptococcus pneumoniae (pneumococcus)

57. General properties G+, arranged in pairs, bullet shape
Capsule: polysaccharide
Blood agar , fastidious
Facultative anaerobes
-hemolysis
Autolysis

58. umbilicus-like colony

59. Distinguish α-hemolytic streptococcus and streptococcus pneumoniae:
Bile solubility test: “+”
Fermentation inulin: “+”

60. Bile solubility test

61. Antigenic structure
Capsular polysaccharide---84 serotypes
C polysaccharide---CRP detection
Resistance
weak

62. Pathogenesis Virulence factor Capsule Pneumolysin O & Neuraminidase
Main disease
Lobar pneumonia
Meningitis, otitis media, sinusitis
bacteriemia, pericarditis, arthritis
Immunity
Gain type specific immunity afer infection

63. Lobar pneumonia

64. Other streptococci Group B streptococci(GBS) Neonatal infections
(meningitis,pneumonia,septicemia)
Group D streptococci
Opportunistic infection---Urinary infeciton,endocarditis,septicemia

65. α-hemolytic streptococci(viridans streptococci
Endocarditis
Dental cary

66. Section 4 Neisseria
N. meningitidis
N. gonorrhoeae

67. Common biological characteristics
G- coffee bean-shaped or kidney-shaped cocci, in pairs
capsules and pili
No spore , no flagella
aerobic
fastidious
5~10%CO2
Resistance: very low

68. N. meningitidis Pathogenesis Virulence factor: Pili
Capsule：13 serogroups (A,B,C---pathogenic to human)
Endotoxin
Disease:
epidemic cerebrospinal meningitis (fever, intense headache, vomiting, stiff neck, coma)

69. N. Gonorrhoeae /gonococcus
Virulence factors
Pili
IgA1 protease
Outer membrane protein (OMP)
LPS (endotoxin)
Diseases
Gonorrhea

70. Gonorrhea Adults Newborns
Transmission: STD (sexually transmitted disease)
Clinical disease: Genitourinary tract infection
Urethritis, prostatitis; epididymitis (male);
cervix inflammation (female);
sterility
Newborns
Ophthalmia neonatorum

72. Prevention and treatment
Penicillin
1%Silver nitrate-- ophthalmia neonatorum

73. This chapter will focus on
Concepts:
Pathogenic/Pyogenic cocci
SPA
ASO test
Question:
Try to describe pathogenicity of 5 pathogenic cocci
(S.aureus, S.pyogenes, S.pneumoniae,
N.meningitidis, N.gonorrhea)