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Bacte LEC > Staphylococcus > Flashcards

Staphylococcus Flashcards

1
Q

• ^ peptidoglycan; + v level of lipid (cell wall)

A

Gram Positive Cocci

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2
Q

Gram + cocci

Lead to accumulation of neutrophils, bacterial cells, and fluids at the site
> ___________

A

Pyogenic infection

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3
Q

All gram positive cocci (14)

A
  1. Staphylococcus
    1. Streptococcus
    2. Stomatococcus
    3. Salinicoccus
    4. Leuconostoc
    5. Lactococcus
    6. Aerococcus
    7. Alloiococcus
    8. Planococcus
    9. Pediococcus
    10. Micrococcus
    11. Macrococcus
    12. Gemella
    13. Rothia
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4
Q

Reclassification of Gram Positive Cocci
• In 1996:

A

Bergey’s Manual of Systematic Bacteriology

• Family Micrococcaceae includes 4 genera:
• Micrococcus
• Planococcus
• Staphylococcus
• Stomatococcus

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5
Q

In 1996: Bergey’s Manual of Systematic Bacteriology
• Family Micrococcaceae includes 4 genera:

A

• Micrococcus
• Planococcus
• Staphylococcus
• Stomatococcus

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6
Q

• Ribosomal RNA & DNA Hybridization Analysis
• Recent Edition:
• 2 families:

A

• Family Staphylococcaceae
• Family Micrococcoceae

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7
Q

Family Staphylococcaceae
• Includes :

A

• Genus Gemella
• Genus Staphylococcus
• Genus Salinicoccus
• Genus Macrococcus

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8
Q

Family Micrococcaceae
• Includes:

A

• Genus Micrococcus
• Genus Arthrobacteria
• Genus Kocuria

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9
Q

Stomatococcus mucilaginosus
• Only member of the Genus Stomatococcus
• Reclassified under the Genus Rothia
_____________

A

Rothia mucilaginosus

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10
Q

Mucilanigosus

• [can/cannot] grow in the presence of 5% NaCl

• Weakly_____ (+),______ (-) and has a_____

• Emerging pathogen in______

A

Cannot

catalase, coagulase; capsule

immunosuppressed patients

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11
Q

M vs S

Bacitracin (0.04 unit)

Micrococcus
Staphylococcus

A

Susceptible
Resistant

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12
Q

M vs S

Furazolidone (100 ug/mL)

Micrococcus
Staphylococcus

A

Resistant
Susceptible

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13
Q

M vs S

Lysostaphin (200 ug/mL)

Micrococcus
Staphylococcus

A

Resistant
Susceptible

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14
Q

M vs S

Carbohydrate Utilization (OF Medium)

A

Oxidative
Fermentative

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15
Q

M vs S

Modified Oxidase (Microdase) test

Micrococcus
Staphylococcus

A

Positive
Negative

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16
Q

M vs S

Growth on Furoxone-Tween 80-oil red 0 agar

Micrococcus
Staphylococcus

A

Positive
Negative

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17
Q

Staphylococcus
Significant human species: SHHEAW

A
  1. S. saprophyticus
    1. S. hominis
    2. S. hemolyticus
    3. S. epidermidis
    4. S. aureus
    5. S. warneri
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18
Q

Staphylococcus: General Characteristics
Clinically Significant:

A

• S. aureus
• S. epidermidis
• S. saprophyticus

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19
Q

Staphylococcus

• Catalase____
• G (+) соссі
• motile? Spore forming?
• O2 requirement???
• Modified oxidase___
• Reduces___ to ____
• Grows in ____ to ____NaCl
• Lysostaphin____
• Bacitracin____

A

(+)

Nonmotile & Non-spore forming

Facultative anaerobes

(-)

nitrates to nitrites

7.5% to 10%

sensitive

resistant

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20
Q

Staphylococcus

• Transmission:

• Infections:

A

Direct contact
Fomites
poor hygiene

virulence of strain
size of inoculum
Immune status

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21
Q

Staphylococcus aureus
VIRULENCE FACTORS

A

• Surface structures
• Enzymes
• Toxins

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22
Q

Staphylococcus aureus
SURFACE STRUCTURES

A
  1. Protein A
  2. Capsular polysaccharide
  3. Peptidoglycan & Teichoic acid*
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23
Q

SAU Enzymes

A

Enzymes
• Catalase
• Bound coagulase
• Staphylokinase
• Lipase
• Hyaluronidase
• DNase
• Beta lactamase

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24
Q

SAU toxins

A

Toxins
• Exfoliatin
• Leukocidin
• Hemolysins
• Enterotoxins
• Superantigens

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25
Q

Staphylococcus aureus
SURFACE STRUCTURES

• binds to Fc region of IgG
• affects the immediate & delayed hypersensitivity reactions

A

Protein A

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26
Q

SAU surface structure

• Anti-phagocytic
•Enhance binding to host cells & prosthetics
protein A
antibody.

A

Capsular polysaccharide

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27
Q

SAU

• Chemoattractant for neutrophils; Activates complement
• Elicits production of IL-1 & opsonic Abs by monocytes
• mediates adhesion by binding to tissue fibronectin*

A

Peptidoglycan & Teichoic acid*

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28
Q

Staphylococcus aureus
DISEASE PROCESS

A

• SAU → invades tissues & produce toxins

• Organism spread (site of carriage) → site of infection (breaks on the skin)

• Organism → blood → lungs, bones, liver, brain, or heart

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29
Q

Staphylococcus aureus
DISEASES

Types of Staphylococcal Diseases:

A

• Local Abscesses
• Focal Suppuration
• Diseases caused by toxin elaboration

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30
Q

SAU

LOCAL ABSCESSES

A

• Folliculitis
• Furuncles (Boils)
• Carbuncles
• Sty

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31
Q

SAU

FOCAL SUPPURATION

A

• Osteomyelitis
• Pneumonia
• Meningitis
• Empyema
• Endocarditis
• Sepsis
• Impetigo / Pyoderma

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32
Q

EXOTOXIN ELABORATION

• Enterotoxins A & B
Nausea, vomiting & abdominal pain

A

• FOOD POISONING

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33
Q

EXOTOXIN ELABORATION

• Enterotoxins A & B
Nausea, vomiting & abdominal pain

A

• FOOD POISONING

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34
Q

EXOTOXIN ELABORATION

Epidermolytic toxin/ exfoliatin = Exfoliation

A

• SCALDED SKIN SYNDROME

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35
Q

EXOTOXIN ELABORATION

• multisystemic disease
• TSST-1 producing strains of SAU

A

• TOXIC SHOCK SYNDROME

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36
Q

GENERAL CHARACTERISTICS

• Normal flora of skin & mucous membranes
• G (+) cocci in clusters

A

Staphylococcus epidermidis

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37
Q

Staphylococcus epidermidis
GENERAL CHARACTERISTICS

• Virulence factor

A

• Biofilm production
• cell surface & extracellular compounds
• promote adherence of bacteria to surfaces of prosthetic devices.

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38
Q

Staphylococcus epidermidis

•______ growth on BAP
•____ growth on CNA
• _______on MSA
• Coagulase___
• DNase___
•____ to Novobiocin

A

White creamy non-hemolytic

+

Can grow but lacks fermentation

(-)

Susceptible

(-)

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39
Q

Staphylococcus epidermidis
DISEASES

catheters
prosthetic heart valve implantation
prosthetic devices: CNS shunts, intravascular catheters vimmunosuppression

A

HOSPITAL ACQUIRED

40
Q

GENERAL CHARACTERISTICS
• Contaminant
• important cause of UTI among sexually active females
• Catheter-associated UTI

A

Staphylococcus saprophyticus

41
Q

Staphylococcus saprophyticus

• Catalase___
• Coagulase___
• DNase___
• ___on BAP
• MSA____
•____ to 5 ug NOVOBIOCIN

A

(+)

(-)

(-)

Non-hemolytic

fermentation variable

Resistant

42
Q

• Strains of SAU that are resistant to beta lactams

A

Methicillin Resistant
Staphylococcus aureus (MRSA)

43
Q

• Many SAU strains produce______ and are _____

A

B-lactamase & are penicillin-resistant

44
Q

• Significant nosocomial infection (HA-MRSA)
• CA-MRSA

A

Methicillin Resistant
Staphylococcus aureus (MRSA)

45
Q

Methicillin Resistant
Staphylococcus aureus (MRSA)

Antibiotics

A

Oxacillin, cloxacillin & methicillin

46
Q

Staphylococcus

Specimen Collection & Processing
Specimens:

+ NOTED

A

• Wound
• Blood
• Sputum
• Urine

• Do direct gram stain from specimen
• Gram (+) cocci & neutrophils are noted

47
Q

Staphylococcus: Culture Medium

A

Sheep’s Blood Agar Plate

Colistin Nalidixic Acid Agar (CNA)

Growth on MSA

Chromogenic Agar (Hardy Chrome Staph aureus agar)

48
Q

• Medium, convex, creamy, dome shaped
• Pigment: white to golden yellow

A

Sheep’s Blood Agar Plate

49
Q

• Selective medium for growth of G(+) bacteria
• The medium is blood agar base with Antibiotics

A

Colistin Nalidixic Acid Agar (CNA)

50
Q

• Selective & differential medium
• 1 salt (7.5%) = selective
• Mannitol & phenol red

A

Growth on MSA

51
Q

Chromogenic Agar (Hardy Chrome Staph aureus agar)
______ appears deep pink to fuchsia colonies
______partially or completely inhibited
______appears turquoise colonies

A

• SAU

• S. epidermidis

• S. saprophyticus

52
Q

Staphylococcus aureus
MACROSCOPIC CHARACTERISTICS
COLONIES

A

• Medium to large smooth, butyrous, creamy
• Margin is entire
• Staphyloxanthin (yellow pigment)
• Narrow zone of B-hemolysis (SBA

53
Q

Test for Differentiation: Catalase Test

A

• Differentiate Staphylococcus from Streptococcus

54
Q

Test for Differentiation: Coagulase Test

A

• Differentiate Staphylococcus aureus from CoNS

55
Q

• Latex agglutination
• Latex particle (coated with human plasma fibrinogen & IgG) → reacts with clumping factor & protein A of
SAU

A

Rapid Detection of Coagulase Activity

56
Q

Ex. BBL Staphyloslide Latex Test
• _____________→ cross-linking → agglutination w/ latex particle

A

Blue Latex reagent + SAU colonies

57
Q

Test for Differentiation:
Modified Oxidase Test

A

• Differentiate Micrococcus from Staphylococcus

58
Q

Modified oxidase test reagent

A

Reagent:
• 6% tetramethyl-p-phenylenediamine dihydrochloride in dimethyl sulfoxide

59
Q

Modified Oxidase Test

Result:
• (+) =
• (-) =

A

dark blue - purple color
(Cytochrome C)

no change in color

60
Q

Test for Differentiation:
Bacitracin Susceptibility Test
• Differentiate_______ _____ and ______

A

Micrococcus & Rothia
from Staphylococcus

61
Q

Test for Differentiation:
Bacitracin Susceptibility Test
• Differentiate _____ and _____ to _____
•____ u Bacitracin disk
• Interpretation:
•_____ = Susceptible
• _____= Resistant

A

Micrococcus & Rothia from Staphylococcus

0.04

Zones > 10 mm

Zones < 10 mm or no zone of inhibition

62
Q

Test for Differentiation:
Bacitracin____
• Differentiate Micrococcus & Rothia
from Staphylococcus
• 0.04 u Bacitracin disk
• Interpretation:
• Zones > 10 mm = Susceptible
• Zones < 10 mm or no zone of inhibition = Resistant

A

Susceptibility Test

63
Q

Test for Differentiation:
Bacitracin Susceptibility Test

Micrococcus & Rothia :
Staphylococcus :

A

S

R

64
Q

MOT

Result:

(Cytochrome C)

A

• (+) = dark blue - purple color

65
Q

Test for Differentiation:
Novobiocin Susceptibility Test

A

• Differentiate S. saprophyticus from other CoNS

66
Q

Test for Differentiation:
Novobiocin Susceptibility Test

• S. saprophyticus:_____
• other CoNS :_____
• Place____ of Novobiocin

A

Resistant

Sensitive

5ug

67
Q

Novobiocin Susceptibility Test

Interpretation:

A

• Susceptible = zone > than 16 mm
• Resistant = zone < or = to 16 mm

68
Q

Test for Differentiation:

• For the presumptive identification of S. aureus and differentiates it from CoNS.
• Methyl Green:
• Toluidine Blue O:
• Detection of thermostable nuclease

A

DNAse Test

colorless

bright pink color.

69
Q

Detection of Antibiotic Resistant SAU
MRSA

A
  1. Cefoxitin Disk Screen Test
  2. Latex agglutination for PBP2a
  3. MH agar with NaCl & 6 ug/mL of
    Oxacillin
  4. Chromogenic Agar
  5. Detection of mecA gene or its product PBP2a
70
Q

Treatment and Prevention

• Handwashing; local antisepsis
• Drainage of pus
• Surgical drainage, removal of tissue

A

-For S. aureus:

71
Q

SAU

Antimicrobial Therapy:

A

• Methicillin, nafcillin, cloxacillin
• Vancomycin
• Tetracyclines

72
Q

For
• Difficult to treat. Removal of the prosthetics may be done.
• 40% of CoNS are resistant to B-lactamase resistant antibiotics

A

S. epidermidis:

73
Q

S. epidermidis:

• Treatment:

A

• Penicillin G
• semisynthetic penicillinase-resistant penicillins
• cephalosporins
• Vancomycin

74
Q

• The majority of _______infections can be adequately treated with antibiotics.
• Untreated → progress to pyelonephritis.

A

S. saprophyticus

75
Q

S. saprophyticus

• The antibiotic of choice: v Nitrofurantoin (Macrobid)
~ Trimethoprim-sulfamethoxazole (TMP-SMX)

A

• The antibiotic of choice: v Nitrofurantoin (Macrobid)
~ Trimethoprim-sulfamethoxazole (TMP-SMX)

76
Q

will break down Hydrogen peroxide into water and oxygen (Bubble formation)

Hydrogen peroxide is needed by the immune cells to function properly - no H202 means no immune action - no opsonization,

A

Catalase

77
Q

will convert Fibrinogen into Fibrin which will result in a clot.

A clot in the body is toxic to the immune cells

A

Coagulase

78
Q

Clotting factor

A

Bound Coagulase

79
Q

TWO TYPES OF COAGULASE
(Clotting Factor)
(Tube Coagulase)

A
  1. Bound coagulase
  2. Free coagulase
80
Q

Enzyme that dissolves the clot.
The clot becomes small particles - these STILL become toxic for the immune cells

Spreads infection throughout the body

A

Staphylokinase

81
Q

Hydrolyze lipids in the skin / if ever the lipids have been hydrolyzed, this manifests

SKIN INFECTIONS caused by the Staphylococcus

boils, carbuncles, furuncles

A

Lipase

82
Q

Hydrolyzes hyaluronic acid - it is responsible for the spread infection

A

Hyaluronidase

83
Q

Also known as Penicillinase

Breaks down B-lactam rings in which these are found in antibiotics, specifically in penicillin making penicillin ineffective for Staphylococcus aureus

A

Beta lactamase

84
Q

Cleave stratum granulosum of the skin

Excessive peeling of skin

Associated with Staphylococcal Scalded Skin Syndrome

A

Exfoliatin

85
Q

Toxin responsible for continuously puncturing holes in the immune cells rendering them dead and inhibit phagocytosis

A

Leukocidin

86
Q

Toxin responsible for continuously puncturing holes in the immune cells rendering them dead and inhibit phagocytosis

A

Hemolysins

87
Q

Among the seven heat stable, only two are very common that can cause food poisoning → A and B

A

Enterotoxins

88
Q

Responsible for making cytokines in the body - too much cytokines will let them accumulate, and increased cytokines will cause havoc

A

Superantigens

89
Q

→ Inflammation of hair follicles - where it is supposed to grow

→ Back, arms, buttocks

A

Folliculitis

90
Q

→ Presence of pus → a.k.a Abscess

A

Furuncles (Boils)

91
Q

→ Collection of boils left untreated
→ Common at the region of the nape

A

Carbuncles

92
Q

→ Skin is affected, then the bone is inflamed next
→ Left untreated, will require amputation
→ Common in patients with diabetes

A

Osteomyelitis

93
Q

→ Presence of pus in the lungs

A

Empyema

94
Q

→ Common in toddlers/infants that are yet to develop immunity

A

Impetigo/ Pyoderma

95
Q

• Medium-large in size, convex, creamy, dome shaped

Beta-hemolytic, some Staphylococcus spp. have no hemolysis

Pigment: white to golden yellow

A

Sheep’s Blood Agar Plate

96
Q

Selective medium for growth of G(+) bacteria

The medium is blood agar base with Antibiotics

A

Columbia Colistin Nalidixic Acid Agar (CNA)

97
Q

Selective & differential medium

1 salt (7.5%) = selective

Mannitol and phenol red

A

Growth on MSA

Bacte LEC (29 decks)

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