Bacteriology2, Session 1, 26bahman1392, Professor Havaii(PHD)

1. STAPHYLOCOCCI

2. STAPHYLOCOCCUS
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Introduction
Classification
Antigenic Structure
Staphylococcal Enzymes
Staphylococcal Toxins
Pathogenesis
Resistance to antibiotics
Treatment

3. Staphylococcus
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F. Micrococcaceae
G. Staphylococcus
G. Micrococcus
G. Stomatococcus
G. Planococcus
(facultative anaerobic)
(only aerobic)
(facultative anaerobic)
(only aerobic)

4. INTRODUCTION
• Staphyloccocci - derived from Greek
“stapyle” (bunch of grapes)
• Gram positive cocci arranged in clusters
• Hardy organisms surviving many non
physiologic conditions
• Include a major human pathogen and skin
commensals

5. Gram Stain of Staphylococcus Culture
Gram-positive cocci predominately in clusters

6. Spread of Hospital Strain of Staphylococcus aureus
Nurse
(Carrier)
Doctor:
Boil
Salesman:
Carrier
and
Paronychia
Son:
Impetig
o

7. Properties of Staphylococcus species
Species
S. aureus
Catalase Coagulase
positive
S. epidermidis positive
Mannitol Novobiocin
positive
positive
sensitive
negative
negative
sensitive
S. saphrophyticus positive negative
negative resistant

8. Grouping for Clinical
Purposes
• 1. Coagulase positive Staphylococci
– Staphylococcus aureus
• 2. Coagulase negative Staphylococci
– Staphylococcus epidermidis
– Staphylococcus saprophyticus

9. A. Staphylococcus aureus
• Major human pathogen
• Habitat - part of normal flora in some humans and
animals
• Source of organism - can be infected human host,
carrier, or environment

10. 2. Staphylococcus epidermidis
• Skin commensal
• Infection of an implanted device such as
heart valve, intravenus catheter.
• Ass. With infection of prosthetic
• Causes urinary tract infection in
cathetarised patients
• Usually resistant to many drugs.

11. 3. Stapylococcus saprophyticus
• Skin commensal
• Imp. Cause of UTI in sexually active young
women
• UTI in men (usually after age 50)
• Cystitis, pyelonephritis

12. Resistance to antibiotics
– β- lactamase production - plasmid mediated
Has made S. aureus resistant to penicillin group
of antibiotics - 90% of S. aureus
• Resistance to Naficillin-OxacillinMethicillin
• (Chromosomal mediated)
• Tolerance
• Resistance to Tetracyclin- ErythromycinAminoglycosides ( plasmid mediated )

13. • Tested in lab using methicillin
• Referred to as methicillin resistant S. aureus
(MRSA)
• Emerging problem in the world
• In Sri Lanka prevalence varies from 20- 40%
in hospitals
• Drug of choice - vancomycin
• In Japan emergence of VIRSA(vancomycin
intermediate resistant S. aureus)
• No effective antibiotics discovered -We
might have to discover

14. Antigenic structure
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Capsule
Peptidoglycan
Teichoic acid
Protein A

15. Staphylococcus Structural Virulence Factors
= peptidoglycan
= capsule
= PNSG (biofilm)
= clumping factor
= fibronectin binding protein
= protein A
= collagen binding protein
= teichoic acid

16. Structural Carbohydrates and Virulence
Peptidoglycan
Inflammatory
Teichoic Acid
Inflammatory & allergen
Capsule*
Anti-phagocytic
PNSG*
Biofilm
* - Antibodies to these carbohydrates are protective

17. Staphylococcal binding sites
• The binding sites allow staphylococci to
persist in areas where these substances
abound.
• Fibronectin,
• C1q
• Lamanin (glycoprotein in mammalian
basement membranes)
• Colagen

18. S. aureus Exoproteins and Virulence
Hemolysins:
alpha-hemolysin
beta-hemolysin
gamma-hemolysin
delta-hemolysin
Proteases
Coagulase
Hyaluronidase(s)
Staphylokinase
Lipase(s)
Protease V8
tissue damage at
site of infection
tissue damage
correlates with virulence
spreading factors
destroy host defense

19. Staphylococcal Enzymes
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Coagulase
Catalase
Hyaluronidase
Fibrinolysine
Lipases
Nucleases
Penicillinase

20. Toxins
- Cytotoxins (α , β ,γ)
- Leukocidin
- Exfoliative toxins (ETA , ETB)
- Enterotoxins (A-F , G-I and three subtype
C)
- SEB (super Ag)
- Toxic Shock Syndrom toxin-1 (super Ag)

21. α , β ,γ -hemolysin
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Toxic for :
leukocytes , erythrocytes,
macrophages and platelets
Lymphocytes

22. DISEASES
• Due to direct effect of
organism
– Local lesions of
skin
– Deep abscesses
– Systemic infections
• Toxin mediated
– Food poisoning
– toxic shock
syndrome
– Scalded skin
syndrome

23. Sites of Staphylococcus Infections and Toxic Reactions
Brain and Eye Infections
Endocarditis
Scalded Skin Syndrome (toxin) Nasopharynx 4+
Pneumonia
Food Poisoning (toxin)
Toxic Shock Syndrome vagina 4+
Pyoderma
Bone/Joint Infection

24. Conditions Leading to S. aureus Infections
Skin damage: burns, cuts, sutures
Reduced Chemotaxis: burns, diabetes, cancer
Reduced Phagocytosis: diabetes, complement
deficiency, immunoglobulin
deficiency, genetic defect
in phagocytes
Age: very young or very old

26. Staphylococcus aureus Pyodermas
Impetigo - crusting vesicle formation of the skin
Folliculitis - hair follicles infected
Furnuncles - boil
Carbuncle - multiple skin lesions connected by sinuses
in the connective tissue
Paronychia - infection of the nail bed
Cellulitis - spreading connective tissue infection
Eye Infections -

27. Staphylococcus aureus: Bulbus Impetigo

28. Staphylococcus aureus: Bulbous Impetigo

29. Staphylococcus aureus: Pustular Impetigo

31. Folliculitis
• Superficial folliculitis
• Infection of hair follicles
• Commonly caused by staph. aureus
• Children
• Scalp & limb
• Rarely painful
• Heals in a week

32. Photo of Arm Showing Folliculitis

33. Folliculitis Caused by Staphylococcus aureus

34. Staphylococcus aureus: Folliculitis

36. Furuncle (Boil)
• Acute
• Staph. aureus
• Small, follicular noduler -- Pustule-necrotic--discharge pus
• Painful
• Constitutional symptoms
‫میگذارند‬
‫علئمی که روی تمام بدن تاثیر‬

37. Furuncle Caused by Staphylococcus aureus

39. Furuncle (Boil) Caused by Staphylococcus aureus

40. Staphylococcus aureus: Furuncle on Back of Neck

41. Carbuncle
• Extensive infection of a group of contagious follicles
• Staph. aureus
• Middle or old age
• Predisposing factors
– Diabetes
– Malnutrition
– During prolonged steroid therapy

42. • Painful, hard lump
• Suppuration begins after 5-7 days
• Pus discharge from multiple follicular
orificies
• Large deep ulcer

43. Staphylococcus aureus: Carbuncle on Chin

45. Staphylococcus aureus: paryonchia
Pus

46. Blepharitis Caused by Staphylococcus aureus

47. Staphylococcus aureus: Leading Cause of Blepharitis

48. Keratitis Caused by Staphylococcus aureus

49. Staphylococcus aureus: Keratitis

50. Systemic Infections
• 1. With obvious focus
– Osteomyelitis, arthritis
• 2. No obvious focus
• heart (infective endocarditis)
• Brain(brain abscesses)

51. Staphylococcus aureus: Osteomyelitis
L2
L3
Day 0 = No changes
Day 35 = destruction of L2 ( , ),
exotoses of L2 & L3 ( ),
compression (
)

52. B. TOXIN MEDIATED
DISEASES
• 1. Staphylococcal food poisoning
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Due to production of entero toxins
(A-F, G-I, K-M) SEB (super Ag)
heat stable entero toxin acts on gut
produces severe vomiting following a very
short incubation period
– Resolves on its own within about 24 hours

53. Causes of Food Poisoning - - circa 1980
Parasitic
Viral
Chemical
UNKNOWN
Other
C. botulinum
Shigella Salmonella
Staphylococcus
C. perfringens

54. 2. Toxic shock syndrome
• High fever, diarrhoea,vomiting, shock and
erythematous skin rash which desquamate
• Mediated via ‘toxic shock syndrome toxin’
• 10% mortality rate
• Described in two groups of patients
– ass. With young women using tampones
during menstruation
– Described in young children and men

56. Staphylococcus TSST Causes Desquamation

57. Rash Associated with TSST
Notice: men get toxic shock syndrome,
only ~20% are due to vaginal infection

58. Erythomatous Membranes of Toxic Shock Syndrome

59. Toxic Shock Syndrome: Cutaneous and
Soft Tissue Involvement
Woman’s side
showing extensive
tissue rash due to
TSST.

60. 3. Scalded skin syndrome
• Disease of young children
• Mediated via exfoliative toxins
• Mild erythema and blistering of skin
followed by shedding of sheets of epidermis
• Heals 7 - 14 day
• Don’t grow staph. from blister fluid

61. Staphylococcus Exfoliative Toxin
Properties
Exfoliative
Toxin A
Exfoliative
Toxin B
Size (Daltons)
24,000
24, 000
Temperature
stable 100C
labile 60οC
EDTA
labile
stable
DNA
chromosome
plasmid

63. Scalded Skin Syndrome Involving Exfoliative Toxin
Peeling
skin

64. Staphylococcus aureus: Scalded Skin Syndrome

65. Scalded-Skin Syndrome: S. aureus Exfoliative Toxin
Toxin produced during
rather limited infection
from either plasmid or
chromosomal toxin gene.
This condition is
typically reversible with
antibiotic therapy.

66. Thanks for your attention