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BACTE MIDTERMS > TOPIC 1 COAG POS GRAM POS COCCI > Flashcards

TOPIC 1 COAG POS GRAM POS COCCI Flashcards

1
Q

causes community-acquired infections

A

S. aureus

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2
Q

they are known contaminants and cause
nosocomial infections

A

coagulase negative staphylococci or CONS

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3
Q

S. au is a ______ that belong to the family ______

A

catalase-producing, gram(+) cocci ; Staphylococcaceae

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4
Q

GENERAL CHARACTERISTICS: of Staphylococcus

A
  • Aerobic or facultative anaerobic except S. aureus subsp. Anaerobius and S. sacchrolyticus which are
    obligate aerobes
  • Nonmotile, non-spore forming
  • Spherical cells (0.5 to 1.5um) that appear singly, in
    pairs, and in clusters
  • Normal inhabitants of skin, mucous membranes, and
    intestines
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5
Q

in BAP, Staphylococcus colonies are:

A
  • medium-sized (4-8mm)
  • cream-colored, white, or rarely light gold
  • buttery-looking
  • other spp. may have gray colonies
  • some may be ß-hemolytic
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6
Q

Staphylococci vs Micrococci
*Bacitracin Test

A

Staphylococci: R
Micrococci: S

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7
Q

Staphylococci vs Micrococci
*Furozolidone Susceptibility Test

A

Staphylococci: S
Micrococci: R

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8
Q

Staphylococci vs Micrococci
*Lysostaphin Test

A

Staphylococci: S
Micrococci: R

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9
Q

Staphylococci vs Micrococci
*Modified Oxidase Test /
Microdase Test

A

Staphylococci: (-)
Micrococci: (+)

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10
Q

Staphylococci vs Micrococci
*Growth on Furoxone Tween 80-oil Red O Agar

A

Staphylococci: (-)
Micrococci: (+)

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11
Q

Staphylococci vs Micrococci
*Aid in production from Glycerol (with erythromycin)

A

Staphylococci: (+)
Micrococci: (-)

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12
Q

Staphylococci vs Micrococci
*O/F Test

A

Staphylococci: Fermenter
Micrococci: Oxidizer

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13
Q

S. au is cultivated by adding what percentage of HCl?

A

7.5-10% HCl

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14
Q
  • Grow well on most routine media like Nutrient Agar
    (NA) and Trypticase Soy Broth (TSB)
  • on solid media,
    round, smooth, opaque and butyrous
  • on BAP, colonies
    have golden yellow color and β-haemolytic
  • True coagulase positive and most virulent species of
    staphylococci
  • Responsible for various skin, wound and deep tissue
    infection
A

S. au

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15
Q

what are the virulence factors associated w/ S. au?

A
  1. Antigenic Structure
  2. Enzymes
  3. Toxins
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16
Q

Antigenic Structure of S. au

A
  • teichoic acid
  • peptidoglycan
  • protein a
  • clumping factor
  • capsular polysaccharide
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17
Q

Contain ribitol
teichoic acid in
cell wall

A

teichoic acid

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18
Q

Together with
teichoic acid, it
protects the
bacteria from
lysis and
probably aids in
adherence

A

peptidoglycan

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19
Q
  • Group specific
    antigen unique
    to S. aureus
  • Prevents
    antibody-
    mediated
    phagocytosis by
    PMN by
    competing for
    the Fc portion
A

protein a

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20
Q

Component on
cell wall responsible for
clumping of the
whole Staphylococci in
the presence of
plasma

A

clumping factor

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21
Q

Protects S.au from
phagocytosis

A

capsular polysaccharide

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22
Q

Enzymes of S.au

A
  • Coagulase (staphylocoagulase)
  • Hyaluronidase (spreading factor)
  • Staphylokinase (fibrinolysin)
  • Lipase (fat-splitting enzyme)
  • DNASE and phosphatase
  • Protease
  • Gelatinase
  • B-lactamase
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23
Q
  • Coagulates fibrinogen in the plasma
  • Promotes fibrin layer formation around the
    staphylococcal abscess protecting the bacteria from
    phagocytosis
A

coagulase (staphylocoagulase)

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24
Q

what are the 2 types of coagulase present in S. au?

A
  1. cell-bound coagulase or clumping factor
  2. unbound or free coagulase
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25
Q

what type of coagulase is bound to the cell wall and clots human, rabbit, or pig
plasma?

A

cell-bound coagulase or clumping factor

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26
Q

what type of coagulase includes extracellular
enzymes not bound to the cell wall and cause clot
formation when bacterial cells are incubated
with plasma?

A

unbound or free coagulase

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27
Q

Hydrolyzes hyaluronic acid present in the intracellular
ground substance, permitting the spread of infection

A

hyaluronidase (spreading factor)

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28
Q

Fibrinolytic activities by dissolving fibrin clot

A

staphylokinase (fibrinolysin)

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29
Q
  • Produced by both coagulase (+) and coagulase (-) staphylococci
  • Act on lipids present on the surface of the skin,
    particularly fats and oil secreted by the sebaceous
    glands
A

lipase (fat-splitting enzymes)

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30
Q

among the virulence factors of S. au, which is important in the formation of furuncles, carbuncles, and boils?

A

lipase (fat-splitting enzymes)

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31
Q
  • o Lowers viscosity of exudates giving the pathogen more mobility
  • Destroys DNA
A

DNASE and phosphatase

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32
Q

breaks down Penicillin and ß-lactam drugs

A

B-lactamase

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33
Q

4 types of cytolytic toxins of S. au?

A

alpha-hemolysin
beta-hemolysin
delta-hemolysin
gamma-hemolysin

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34
Q
  • damage RBC, platelets, and macrophages and can
    cause severe tissue damage;
  • predominant hemolysin
A

alpha hemolysin

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35
Q
  • acts on sphingomyelin in the plasma membrane of
    RBC
  • aka “hot-cold” lysine : enhanced hemolytic
    activity on incubation at 37°C (heat labile) and
    subsequent exposure to cold (4°C)
  • exhibited in the Christie, Atkins, and Munch-
    Peterson (CAMP) Test
  • lethal and dermonecrotic
  • joins force with a-hemolysin
A

beta-hemolysin

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36
Q
  • less toxic to cells than either a-hemolysin or ß- hemolysin
  • produced by all S. aureus strain that cause RBC
    injury in culture and produce edematous lesions
A

delta-hemolysin ( δ-hemolysin)

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37
Q

what are the other Staphylococcus spp. that also produces δ-hemolysin?

A
  • S. epidermidis
  • S. haemolyticus
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38
Q
  • associated with Panton-Valentine Leukocidin
    (PVL)
A

gamma hemolysin (γ-hemolysin)

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39
Q
  • exotoxin lethal to polymorphonuclear leukocytes
  • pore-forming exotoxin that suppress phagocytosis and
    associated with severe cutaneous infections and
    necrotizing pneumonia
  • associated with community-acquired staphylococcal
    infections
A

Staphylococcal Leukocidin / Panton-Valentine Leukocidin

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40
Q
  • heat-stable exotoxin: 100°C for 30 minutes
  • resistant to hydrolysis by gastric and jejunal enzymes
  • act as neurotoxins that stimulate vomiting through the vagus nerve
  • produced by 30%-50% of S. aureus isolates
A

enterotoxins

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41
Q

enterotoxin associated w/ Staphylococcal food poisoning

A

Enterotoxins A, B, and D

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42
Q

enterotoxins that are associated with toxic shock syndrome?

A

Enterotoxins B and C, sometimes G and I

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43
Q

enterotoxin that is associated with Staphylococcal Pseudomembranous Enterocolitis?

A

Enterotoxin B

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44
Q

Toxic Shock Syndrome Toxin-1 (TSST-1) is also known as>

A

Enterotoxin F or Pyrogenic Exotoxin C

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45
Q
  • Menstruating-associated TSS = TSS associated with
    tampon use
  • Chromosomal-mediated toxin
  • Superantigen that stimulates T-cell proliferation and production of a large amount of cytokines
  • Low concentrations = leakage by endothelial cells
  • Higher concentrations = cytotoxic

[include other names in answering)

A

Toxic Shock Syndrome Toxin-1 (TSST-1) or Enterotoxin F or Pyrogenic Exotoxin C

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46
Q

Exfoliative toxin is also known as?

A

Epidermolytic Toxin A and B or Exfoliatin serotypes A and B

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47
Q
  • Serine protease that divides the intracellular bridges of
    the epidermis and causes excessive sloughing of the
    epidermis (stratum granulosum)
  • Causes Staphylococcal Scalded Skin Syndrome referred to as “Ritter’s Disease”
  • Implicated in Bullous Impetigo
A

Exfoliative toxin or Epidermolytic Toxin A and B
or Exfoliatin serotypes A and B

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48
Q

give the 9 related infections and diseases associated w/ S.au

A
  1. cutaneous infections
  2. toxic shock syndrome
  3. food poisoning
  4. staphylococcal bacteremia
  5. staphylococcal osteomyelitis
  6. staphylococcal pneumonia
  7. septic arthritis
  8. acute staphylococcal endocarditis
  9. uti
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49
Q

what are the cutaneous infections related to S. au?

A
  • foliculitis
  • furuncles
  • carbuncles
  • bullous impetigo
  • impetigo
  • scalded skin syndrome
  • toxic epidermal necrolysis
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50
Q
  • Mild inflammation of a hair follicle or oil gland; infected area is raised and
    red
A

folliculitis

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51
Q

Focal suppurative lesions which has resulted from an infection (folliculitis)
that extend into subcutaneous tissue; large, raised, superficial abscesses

A

furuncles

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52
Q

Larger, more invasive lesions develop from multiple furuncles, which can
progress into deeper tisue; present with fever and chills, indicating systemic
infection

A

carbuncles

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53
Q
  • Larger pustules surrounded by a small zone of erythema
  • Highly contagious infection that spread by direct contact, fomites, or
    autoinoculation
A

bullous impetigo

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54
Q

Superficial cutaneous infection commonly seen in newborns and young
children characterized by the formations of encrusted pustules surrounded
by red border

A

impetigo

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55
Q
  • Bullous exfoliative dermatitis that occurs primarily in newborns and
    previously healthy young children
  • Localized skin lesion: few blisters, pemphigus neonatorum, Ritter disease
  • Generalized form: cutaneous erythema, profuse peeling of the epidermis
A

scalded skin syndrome

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56
Q

Clinical manifestation with multiple causes; symptoms are due to
hypersensitivity reaction

A

toxic epidermic necrolysis

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57
Q

Rare, but potentially fatal, multisystem disease characterized by sudden
onset of fever, chills, vomiting, diarrhea, muscle aches, and rash, which can
quickly progress to hypotension and shock

A

toxic shock syndrome

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58
Q

food poisoning enterotoxin percentage

A

o Enterotoxins A (78%)
o Enterotoxin D (38%)
o Enterotoxin B (10%)

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59
Q
  • Intoxication resulting from ingestion of a toxin formed outside the body
  • Symptoms appear rapidly (2-8 hours after ingestion) and resolve within 24-
    48 hours: nausea, vomiting, abdominal pain, and severe cramping, diarrhea)
A

food poisoning

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60
Q

Leads to secondary pneumonia and endocarditis observed among IV drug
users

A

staphylococcal bacteremia

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61
Q

Secondary to bacteremia

A

staphylococcal osteomyelitis

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62
Q

o Secondary to influenza virus infection
o Multiple abscesses and focal lesions in the pulmonary parenchyma

A

staphylococcal pneumonia

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63
Q

Frequent in children and occur in patients with a history of rheumatoid
arthritis or IV drug abuse

A

septic arthritis

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64
Q

what are the bacteria present in Both adults and Neonates / Children for joined infections/septic arthritis?

A

Staphylococcus aureus
Staphylococcus agalactiae
Enterobacteriacaeae

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65
Q

what are the bacteria present in Neonates / Children only for joined infections/septic arthritis?

A

Haemophilus influenzae type B
Kingella kingae

66
Q

what are the bacteria present in sexually active individuals for joined infections/septic arthritis?

A

Neisseria gonorrohoeae

67
Q

specimen of choice for lab diagnosis of S. au

A

blood, pus, urine, purulent fluids, sputum

68
Q

culture media used for purulent exudates?

A

Columbia Colistin Nalidixic Acid (CNA)

69
Q

culture media used for heavily contaminated specimens?

A

MSA and PEA

MSA: Mannitol Salt Agar
PEA: Phenylethyl Alcholol Agar

70
Q

culture media used for selective-defferential for MRSA

A

CHROM Agar

71
Q

give the 10 biochemical tests used for the laboratory diagnosis of S. au

A

a. catalase test
b. coagulase test
c. mannitol fermentation test
d. growth on tellurite glycine agar
e. polymyxin b sensitivity
f. lystostaphin sensitivity test
g. voges-proskauer test
h. dnase test
i. pyrrolidonyl arylamidase test
j. rapid methods for identification
k. molecular methods

72
Q

in the catalase test for S. au, what reagent is used? what concentration

A

3% H2O2 for aerobic catalase test
15% H2O2 for anaerobic catalase test

73
Q

result in catalase test

A

staphylococcus (+)
streptococcus (-)

74
Q

what test is the best single criterion of recognition and pathogenicity of
S. aureus?

A

coagulase test

75
Q

what are the 2 methods used in coagulase test?

A

slide method
tube method

76
Q
  • a rapid screening test
  • it detects cell-bound coagulase or clumping factor
A

slide method

77
Q

what are other spp. of Staphylococcus that is coagulase (+) ?

A

S. lugdunensis
S. schleiferi

78
Q
  • a sensitive but definitive method
  • detects unbound or free coagulase
A

tube method

79
Q

what are other spp. of Staphylococci seen in animals that are coagulase (+) in tube method?

A

S. hyicus
S. intermedius
S. lutrae
S. schleiferi subsp. coagulans

80
Q

in tube method, incubate for ___ hours at _____^C?

A

1-4 hours at 35-37^C

81
Q

in tube method, if no clot forms after 4 hours, what should you do?

A

incubate for additional 20 hours at RT

82
Q

why should the result be read within 4 hours in the tube coagulase method?

A

to prevent false (-) rxn due to fibrinolysin w/c lyses the clot formed

83
Q

coagulase plasma with citrate is not suitable because?

A

it can cause false (+) result

84
Q

they use citrate
and release calcium forming clot in the absence of coagulase

A

pseudomonas and enterococci

85
Q

fill in the blanks
Mannitol Fermentation Test:
*Culture Medium:
*pH indicator:
*Result:

A

*Culture Medium: Mannitol Salt Agar (MSA)
*pH indicator: phenol red
*Result: yellow-colored colonies surrounded by a yellow halo

86
Q

what color is produced by S. au in the tellucine glycine agar test? how about for other staphylococci?

A
  • jet-black for S. au
  • growth is inhibited for other Staphylococci but if growth occurs, gray colonies are seen
87
Q

indicate the result in polymixin B sensitivity test for S.au

A

S. au - resistant
other Staphylococci - susceptible

88
Q

used to differentiate S. au from micrococci

A

lysostaphin sensitivity test

89
Q

result in lysostaphin sensitivity test

A

S. au - sensitive
Micrococci - resistant

90
Q

it is a test used to differentiate S. au from S. intermedius

A

Voges-Proskauer Test

91
Q

Voges-Proskauer Test
*Culture medium:
*Reagent:

A
  • Culture medium: VP broth w/ 5% glucose
  • Reagent: a-naphthol and KOH
92
Q

VP test result

A

S. au (+)
S. intermedius (-)

93
Q

other VP test positive Staphylococci spp.

A

S. lugdunensis
S. haemolyticus
S. schleiferi

94
Q

culture medium used in DNASE test for S. au

A

DNA-Methyl Green Agar

95
Q

DNASE test result

A

S.au - (+)

96
Q

it is a test used to differentiate coagulase (+) Staphylococci by slide methods

A

Pyrrolidonyl Arylamidase Test

97
Q

Pyrrolidonyl Arylamidase Test
*Substrate:
*Reagent:
*End product:
*Result:

A
  • Substrate: pyroglutamyl-B-naphthylamide
  • Reagent: p-dimethylaminocinnamaldehyde
  • End product: l-pyrrolidone and b-naphthylamine
  • Result: cherry red
98
Q

result in PYR test

A

PYR (-): S.au
PYR (+): S. lugdunensis, S. intermedius, S. schleiferi, S. haemolyticus

99
Q

tests used in rapid methods for identification of S.au

A
  • staphyloside
  • staphylatex
100
Q

makes use of sensitized sheep RBC

A

staphyloside

101
Q
  • Plasma-coated carrier particles (latex)
  • Plasma detects both clumping factor (w/ fibrinogen)
    and protein A in the cell wall of S. aureus (with IgG)
A

staphylatex

102
Q

a molecular method test used in identifying both MRSA and MSSA

A

Real-time PCR

103
Q
  • staphylococci from prepared smears in blood cultures
  • identification of mecA gene
A

QNAHA: Qualitative Nucleic Acid Hybridization Assay

104
Q

Molecular Method:
*Specimen:
*Advantage:

A
  • Specimen: anterior nares swabs
  • Advantage: rapid detection test for MRSA
105
Q

is responsible for adherence of S. epidermidis

A

Poly-y-DL-Glutamic Acid (PGA)

106
Q
  • Indigenous microbiota of the skin
  • Contaminant of medical instruments,
    catheters, CSF shunts, and prostheBc
    heart valve implants (implanted medical
    devices), hip prostheses
A

S. epidermidis

107
Q

what are the diseases associated with S. epidermidis?

A
  • stitch disease
  • healthcare-acquired UTI
  • endocarditis
  • bacteremia
108
Q

secondary to E. coli in causing UTI

A

S. saprophyticus

109
Q

what type of UTI is caused by S. saprophyticus?

A

COMMUNITY-ACQUIRED UTI

110
Q
  • Present on the normal skin and in the
    periurethral and urethral flora
  • Adheres effectively to the epithelial cells
    lining the urogenital tract
  • it is the common cause of UTI in young, sexually active women
A

S. saprophyticus

111
Q

what amount of CFU is considered significant in the urine culture of S. saprophyticus?

A

<10,000 CFU/ml

112
Q

what gene codes for oxacillin resistance?

113
Q
  • Clumping factor (+), tube coagulase (-)
  • Contains mecA gene that encodes oxacillin resistance
  • More aggressive than other CoNS in infectivity
A

S. lugdunensis

114
Q

what are the diseases caused by S. lugdunensis

A

infective endocarditis, septicemia, skin and soft tissue infections, meningitis, UTIs, and septic shock

115
Q

in BAP, they appear gray to white, opaque, small to
medium-sized pin-heads and non-hemolytic colonies

A

S. epidermidis

116
Q

biochemical test for S. epidermidis

A
  • Coagulase test: (-)
  • CNA: (+)
  • DNASE: (-)
  • Mannitol Fermentation: (-)
117
Q

noviobiocin susceptibility of S. epidermidis

A

novobiocin susceptible (5ug susceptible)

118
Q

in BAP, they appear white, opaque, slightly larger than pin-heads, non-hemolytic colonies although
some strains produce yellow pigments

A

S. saprophyticus

119
Q

biochemical test for S. saprophyticus

A
  • Coagulase (-)
  • DNASE (-)
  • Mannitol fermentation (-)
120
Q

noviobiocin susceptibility of S. saprophyticus

A
  • novobiocin resistant
121
Q

absence of phosphatase production
a. S. epidermidis
b. S. saprophyticus

A

b. S. saprophyticus

122
Q
  • causes wounds, bacteremia, endocarditis, and UTIs
  • Medium-sized colonies, with moderate or weak hemolysis and variable pigment production
A

S. haemolyticus

123
Q

NOVOBIOCIN SUSCEPTIBLE CoNS

A

S. epidermidis
S. capitis
S. haemolyticus
S. hominis subsp. hominis
S. lugdunensis
S. saccharolyticus
S. warneri

124
Q

NOVOBIOCIN RESISTANT CoNS

A

S. saprophyticus
S. cohnii
S. kloosii
S. xylosus

125
Q
  • a class of enzyme inactivating genes
  • codes for the methylation of 23s rRNA
  • results in resistance to erythromycin
  • inducible/constitutive resistance to clindamycin
A

ERM Gene: Erythromycin Ribosomal Methylase Gene

126
Q

ERM gene confers cross resistance to _____ and _____

A

macrolides (erythromycin) and streptogramins (quinupristin)

127
Q
  • codes for efflux mechanism: resistance to erythromycin but susceptibility to clindamycin
A

MSR Gene: Methionine Sulfoxide Reductase Gene

128
Q

give the resistant genes produced by Staphylococci

A
  • Erythromycin Ribosomal Methylase Gene
  • Methionine Sulfoxide Reductase Gene
129
Q
  • Type of S. aureus that is resistant to methicillin,
    nafcillin, and oxacillin
  • Acquired after prolonged stay in the hospital, close
    contact with carriers, effects of broad spectrum
    antibiotic treatments and exposure to nasal secretions
A
  • MRSA: Methicillin-Resistant S. au
130
Q

treatment of choice for MRSA

A

Vancomycin

131
Q

what are the 3 types or MRSA?

A
  • Community-Associated MRSA (CA-MRSA)
  • Healthcare-Associated Community Onset MRSA (HACO-MRSA)
  • Hospital-Associated MRSA (HA-MRSA)
132
Q
  • used to screen for MRSA in clinical samples
  • differentiate MRSA from hyperproducers of ß-
    lactamase, or Borderline Oxacillin-Resistant
    Staphylococcus aureus (BORSA)
A

Oxacillin-Salt Agar Plate

133
Q

codes for the altered Penicillin-Binding Protein
(PBP) = PBP2a or PBP2’

134
Q

Chromogenic Selective Differential Media in Chromogenic Test

A
  • MRSA Select
  • Spectra MRSA
  • CHROM Agar
135
Q

inhibit non-MRSA

136
Q

result of chromogenic test

A

changes in color of MRSA colonies within 24-48
hours using CHROM Agar against colonies of non-MRSA
(mauve-colored colonies)

137
Q
  • detect altered PBPs
  • Alternative method for testing and confirmation of
    oxacillin resistance
  • Performed on both CoNS and S. aureus
A

latex agglutination

138
Q

gold standard for MRSA detection

A

Molecular Nucleic Acid Probes or PCR Amplification

139
Q

screening for Vancomycin-Resistant Staphylococci

A

Vancomycin Agar Plate

140
Q

discrepant macrolide test results (erythromycin
resistant and clindamycin susceptible)

A

Modified Double Disk Diffusion Test (D-zone test)

141
Q

what are the tests utilize in the laboratory diagnosis for MRSA

A
  • Oxacillin-Salt Agar Plate
  • Chromogenic Test
  • Latex Agglutination
  • Molecular Nucleic Acid Probes or PCR Amplification
142
Q

what are the different types of tests in the beta-lactamase tests?

A
  • Cephalosporinase test
  • Acidimetric Method
  • Iodometric Method
143
Q

Uses cephalosporin or cefinase disk

A

cephalosporinase test

144
Q

substrate for cephalosporinase test

A

nitrocefin

145
Q

(+) Result of Cephalosporinase Test

A

deep pink or red color within 10 minutes (60 minutes for Staphylococci)

146
Q

Acidimetric method
*Reagent:
*pH indicator:
*(+) Result:

A
  • Reagent: citrate-buffered penicillin
  • pH indicator: phenol red
  • (+) Result: yellow
147
Q

Iodometric Method
*Reagent:
*(+) Result:
*(-) Result:

A
  • Reagent: citrate-buffered penicillin and starch iodine complex
  • (+) Result: colorless solution (penicilloic acid reduces iodine and prevents it to combine with starch)
  • (-) Result: purple (no color change)
148
Q

treatment used for cutaneous infections

A
  • oral oxacillin or dicloxacillin
  • if allergic, erythromycin can be substituted
149
Q

treatment used for systemic infections

A
  • parenteral nafcillin or oxacillin
  • if allergic, vancomycin or cephalosporin may be used
150
Q

Screening Test for MRSA

A
  • oxacillin screen plate
  • cefoxitin disk diffusion
  • macro e test
  • vancomycin agar screen plate
151
Q

Oxacillin Screen Plate
*Culture media:
*Microdilution testing:

A
  • Culture Media: MHA with 4% NaCl and 6ug/ml oxacillin
  • Microdilution testing: oxacillin in cation-supplemented MH Broth containing 2% NaCl
152
Q

Oxacillin Screen Plate
*Result:

A

resistant: growth of more than one colony
susceptible: no growth on the agar plate

153
Q

Oxacillin Screen Plate
*CoNS (resistant or susceptible)

A

R: 24 mm ZOI
S: >25mm ZOI

154
Q

disadvantage of oxacillin screen plate?

A

does not reliably detect oxacillin-resistant CoNS

155
Q
  • it is the preferred method for detection of oxacillin-resistance
    for both S. aureus and S. lugdunensis
  • improves detection of MRSA
  • serves to induce greater PB2a in mecA-containing
    strains
A

Cefoxitin Disk Diffusion

156
Q

Cefoxitin Disk Diffusion
*Interpretation

A
  • Resistant: <21mm
  • SuscepBble: >22mm
157
Q

Detection of heteroresistant VISA because the test uses
a higher concentration of organisms (1x10^8 bacteria/ml)

A

Macro E Test

158
Q
  • Best method for detection of either Vancomycin-
    resistant S. aureus (VRSA) or VISA
  • Broth microdilution test
A

Vancomycin Agar Screen Plate

159
Q

in Vancomycin Agar Screen Plate, what should be the result?

A

any growth or colony

159
Q

in Vancomycin Agar Screen Plate, S. au should be screened with _______ ?

A

6ug/ml vancomycin
incorporated into BHIA

160
Q

Colony test for oxacillin resistance

A

broth dilution and E-test

BACTE MIDTERMS (2 decks)

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