This document discusses Staphylococcus bacteria, including their classification, morphology, virulence factors, pathogenesis, and clinical manifestations. It focuses on S. aureus and coagulase-negative staphylococci like S. epidermidis. Key points include: S. aureus is distinguished from other staphylococci by being coagulase-positive; virulence factors include exotoxins and cell-associated components like capsules; infections range from minor skin infections to serious conditions like pneumonia, toxic shock syndrome, and endocarditis. Treatment involves antibiotics like penicillins, cephalosporins, and clindamycin.

2. Staphylococcus

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

4. Gram-Positive Cocci
Enterococcus (Group D CHO)  hemolytic ( or )
Enterococcus faecalis, E. faecium
FAMILY Micrococcaceae (catalase positive)
Coagulase-positive Staphylococcus aureus
Coag.-neg. Staphylococcus epidermidis, S. saprophyticus
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)

5. Morphology

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

7. Streptococcus
Staphylococcus

8. Staphylococcus

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

14. MICROBIAL
PATHOGEN ADHESIN RECEPTOR
Staphylococcus aureus L
Li
ip
po
ot
te
ei
ic
ch
ho
oi
ic
c a
ac
ci
id
d Unknown
Staphylococcus spp. S
Sl
li
im
me
e l
la
ay
ye
er
r Unknown
Group A Streptococcus L
LT
TA
A-
-M
M p
pr
ro
ot
te
ei
in
n c
co
om
mp
pl
le
ex
x F
Fi
ib
br
ro
on
ne
ec
ct
ti
in
n
Streptococcus pneumoniae Protein N-acetylhexosamine-gal
Escherichia coli Type 1 fimbriae
CFA 1 fimbriae
P fimbriae
D-M
Ma
an
nn
no
os
se
e
GM g
ga
an
ng
gl
li
io
os
si
id
de
e
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)  hemolytic ( or )
Enterococcus faecalis, E. faecium
FAMILY Micrococcaceae (catalase positive)
Coagulase-positive Staphylococcus aureus
Coag.-neg. Staphylococcus epidermidis, S. saprophyticus
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)
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