This document discusses the classification, morphology, and virulence factors of Staphylococcus and Streptococcus bacteria. It describes that Staphylococcus includes coagulase-positive S. aureus and coagulase-negative species like S. epidermidis and S. saprophyticus. S. aureus is distinguished by producing coagulase enzyme and causing infections like skin and soft tissue infections. Virulence factors allow S. aureus adhesion and damage tissues through secreted enzymes and exotoxins. Proper hygiene and antibiotic treatment can help control S. aureus infections.

2. Staphylococcus

3. Classification
• Family
• Genus
• Species
Micrococcaceae
Micrococcus and Staphylococcus
S. aureus
S. saprophyticus
S. epidermidis
M. luteusmore
than 20
specie
s

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

5. Morphology

6. Morphology
Staph vs. Strep
Gram-positive cocci
in clusters

7. StreptococcusStaphylococcus

8. Staphylococcus

12. See Overheads
~~~~~~~~~~
TSS
Foodborne Intoxication
~~~~~~~~~~

14. MICROBIAL
PATHOGEN ADHESIN RECEPTOR
Staphylococcus aureus LLiippootteeiicchhooiicc aacciidd Unknown
Staphylococcus spp. SSlliimmee llaayyeerr Unknown
Group A Streptococcus LLTTAA--MM pprrootteeiinn ccoommpplleexx FFiibbrroonneeccttiinn
Streptococcus pneumoniae Protein N-acetylhexosamine-gal
Escherichia coli Type 1 fimbriae
CFA 1 fimbriae
P fimbriae
D-MMaannnnoossee
GM ggaanngglliioossiiddee
P blood grp glycolipid
Other Enterobacteriaceae Type 1 fimbriae D-Mannose
Neisseria gonorrhoeae Fimbriae GD1 ganglioside
Treponema pallidum P1, P2, P3 Fibronectin
Chlamydia spp. Cell surface lectin N-acetylglucosamine
Mycoplasma pneumoniae Protein P1 Sialic acid
Vibrio cholerae Type 4 pili 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 ribitol teichoic acid
(polysaccharide A)
S. epidermidis 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. • Enterotoxin
• Exfoliative toxin (epidermolytic toxin)
• Pyrogenic exotoxins
Virulence Factors: 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

24. Coagulase-Negative Staphylococci
• Staphylococcus epidermidis
• S. saprophyticus

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

28. Mannitol Salts Agar
(MSA)
Staphylococcus aureus

29. Catalase
2H2O2  O2 + 2H2O
Streptococci vs. Staphylococci
Differential Characteristics

30. Catalase POS
Staphylococcus
Catalase NEG

31. S. aureus
Coagulase
Fibrinogen  Fibrin
Differential
Characteristics

32. Coagulase NEG
Coagulase POS
Staphylococcus
aureus

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

36. REVIEW

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

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

39. REVIEW

40. REVIEW

41. REVIEW

42. REVIEW

43. REVIEW