Staphylococcus. Classification

1.

2.

Staphylococcus

3. Classification

• Family
Micrococcaceae
• Genus
Micrococcus and Staphylococcus
• Species
more
than 20
specie
s
S. aureus
S. saprophyticus
S. epidermidis
M. luteus

4.

Gram-Positive Cocci
FAMILY Streptococcaceae (catalase negative)
Group A: -hemolytic Streptococcus pyogenes
Group B: -hemolytic (occasionally or ) S. agalactiae
Group C: -hemolytic ( or ) S. anginosus, S. equismilis
Group D: or hemolytic ( ) S. bovis
Group F: -hemolytic S. anginosus
Group G: -hemolytic S. anginosus
Viridans streptococci: (no group specific CHO)
or hemolytic S. mutans and
S. salivarius, S. sanguis, S. mitis and S. milleri groups
Streptococcus pneumoniae (no group CHO)( -hemolytic)
Enterococcus (Group D CHO) hemolytic ( or )
Enterococcus faecalis, E. faecium
FAMILY Micrococcaceae (catalase positive)
Coagulase-positive Staphylococcus aureus
Coag.-neg. Staphylococcus epidermidis, S. saprophyticus

5.

Morphology

6.

Morphology
Staph vs. Strep
Gram-positive cocci
in clusters

7.

Staphylococcus
Streptococcus

8.

Staphylococcus

9.

10.

11.

12.

See Overheads
~~~~~~~~~~
TSS
Foodborne Intoxication
~~~~~~~~~~

13.

14.

MICROBIAL
PATHOGEN
Staphylococcus aureus
Staphylococcus spp.
Group A Streptococcus
Streptococcus pneumoniae
Escherichia coli
Other Enterobacteriaceae
Neisseria gonorrhoeae
Treponema pallidum
Chlamydia spp.
Mycoplasma pneumoniae
Vibrio cholerae
ADHESIN
RECEPTOR
Lipoteichoic acid
Unknown
Slime layer
Unknown
LTA-M protein complex Fibronectin
Protein
Type 1 fimbriae
CFA 1 fimbriae
P fimbriae
Type 1 fimbriae
Fimbriae
P1, P2, P3
Cell surface lectin
Protein P1
Type 4 pili
N-acetylhexosamine-gal
D-Mannose
GM ganglioside
P blood grp glycolipid
D-Mannose
GD1 ganglioside
Fibronectin
N-acetylglucosamine
Sialic acid
Fucose and mannose

15. Cell-Associated Virulence Factors

• Capsule or slime layer (glycocalyx)
• Peptidoglycan (PG)
• Teichoic acid is covalently linked to PG
and is species specific:
S. aureus
S. epidermidis
ribitol teichoic acid
(polysaccharide A)
glycerol teichoic acid
(polysaccharide B)
• Protein A is covalently linked to PG
• Clumping factor (bound coagulase)

16. Virulence Factors Extracellular Enzymes

• Coagulases (bound or free)
Antigenic
• Hyaluronidase
“spreading factor” of S. aureus
• Nuclease
Cleaves DNA and RNA in S. aureus
• Protease
Staphylokinase (fibrinolysin)
• Lipases
• Esterases

17. Virulence Factors: Exotoxins

• Cytolytic (cytotoxins; cytolysins)
Alpha toxin - hemolysin
• Reacts with RBCs
Beta toxin
• Sphingomyelinase
Gamma toxin
• Hemolytic activity
Delta toxin
• Cytopathic for:
–
–
–
–
–
RBCs
Macrophages
Lymphocytes
Neutrophils
Platelets
• Enterotoxic activity
Leukocidin

18.

Virulence Factors: Exotoxins
• Enterotoxin
• Exfoliative toxin (epidermolytic toxin)
• Pyrogenic exotoxins

19. Pathogenesis

• Pass skin – first line of defense
Benign infection
• Phagocytosis
• Antibody
• Inflammatory response
Chronic infections
• Delayed hypersensitivity

20. Clinical Manifestations/Disease

• SKIN
folliculitis
boils (furuncles)
carbuncles
impetigo (bullous & pustular)
scalded skin syndrome
•Neonates and children under 4 years

21. Clinical Manifestations/Disease

• Other infections
Primary staphylococcal pneumonia
Food poisoning vs. foodborne disease
Toxic shock syndrome

22. Metastatic Infections

•Bacteremia
•Osteomyelitis
disease of growing bone
• Pulmonary and cardiovascular
infection

23.

24. Coagulase-Negative Staphylococci

• Staphylococcus epidermidis
• S. saprophyticus

25.

26.

27. Staphylococcal Lab ID & Diagnostic Tests

Staphylococcal Lab ID & Diagnostic Tests
• Microscopic
• Lab isolation
• Coagulase positive
S. aureus

28.

Mannitol Salts Agar
(MSA)
Staphylococcus aureus

29. Differential Characteristics

Catalase
2H2O2 O2 + 2H2O
Streptococci vs. Staphylococci

30.

Catalase POS
Staphylococcus
Catalase NEG

31.

Differential
Characteristics
S. aureus
Coagulase
Fibrinogen Fibrin

32.

Staphylococcus
aureus
Coagulase POS
Coagulase NEG

33. Treatment

• Drain infected area
• Deep/metastatic infections
semi-synthetic penicllins
cephalosporins
erythromycin
clindamycin
• Endocarditis
semi-synthetic penicillin + an aminoglycoside

34. Prevention

• Carrier status prevents complete control
• Proper hygiene, segregation of carrier
from highly susceptible individuals
• Good aseptic techniques when
handling surgical instruments
• Control of nosocomial infections

35.

36.

REVIEW

37.

Gram-Positive Cocci
FAMILY Streptococcaceae (catalase negative)
Group A: -hemolytic Streptococcus pyogenes
Group B: -hemolytic (occasionally or ) S. agalactiae
Group C: -hemolytic ( or ) S. anginosus, S. equismilis
Group D: or hemolytic ( ) S. bovis
Group F: -hemolytic S. anginosus
Group G: -hemolytic S. anginosus
Viridans streptococci: (no group specific CHO)
or hemolytic S. mutans and
S. salivarius, S. sanguis, S. mitis and S. milleri groups
Streptococcus pneumoniae (no group CHO)( -hemolytic)
Enterococcus (Group D CHO) hemolytic ( or )
Enterococcus faecalis, E. faecium
FAMILY Micrococcaceae (catalase positive)
Coagulase-positive Staphylococcus aureus
Coag.-neg. Staphylococcus epidermidis, S. saprophyticus
REVIEW

38.

Which features are only found in S. aureus?
S. aureus
S. epidermidis
REVIEW

39.

REVIEW

40.

REVIEW

41.

REVIEW

42.

REVIEW

43.

REVIEW