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BACTERIOLOGY - LEC > MIDTERMS C1 - Catalase - Positive, Gram-Positive Cocci > Flashcards

MIDTERMS C1 - Catalase - Positive, Gram-Positive Cocci Flashcards

1
Q

Coagulase-Positive Staphylococci

A

Staphylococcus aureus

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2
Q

Coagulase-Negative Staphylococci

A

Staphylococcus epidermidis
Staphylococcus haemolyticus
Staphylococcus saprophyticus
Staphylococcus lugdunensis
Staphylococcus schleiferi
Staphylococcus capitis
Staphylococcus caprae
Staphylococcus warneri
Staphylococcus hominis
Staphylococcus auricularis
Staphylococcus cohnii
Staphylococcus xylosus
Staphylococcus simulans
Micrococcus spp. and related
genera
Alloiococcus

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3
Q

Staphylococcus is a catalase-producing gram (+) cocci that belong to the family

A

Staphylococcaceae

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4
Q

Staphylococcus is aerobic or facultative anaerobic except what species?

A

S. aureus subsp. anaerobius and S. sacchrolyticus which are obligate anaerobes

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5
Q

nonmotile, non–spore-forming

spherical cells (0.5 to 1.5 μm) that appear singly, in pairs, and in clusters

normal inhabitants of skin, mucous membranes and intestines

A

Staphylococcus

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6
Q

In Blood Agar Plate, what are the colonies size and characteristics?

A

medium sized (4 to 8 mm) and appear cream-colored, white or rarely light gold, and “buttery looking”, other spp. may have gray colonies; some may be β-hemolytic (S. aureus

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7
Q

(Staphylococci/Micrococci)
Bacitracin Test Resistant

A

Staphylococci

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8
Q

(Staphylococci/Micrococci)
Bacitracin Test Susceptible

A

Micrococci (>10mm)

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9
Q

(Staphylococci/Micrococci)
Furazolidone Susceptibility Test (100ug) - SUSCEPTIBLE

A

Staphylococci (>15mm)

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10
Q

(Staphylococci/Micrococci)
Furazolidone Susceptibility Test (100ug) - RESISTANT

A

Micrococci (6-9 mm)

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11
Q

(Staphylococci/Micrococci)
Lysostaphin Sensitivity Test - Susceptible

A

Staphylococci (10-16 mm)

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12
Q

(Staphylococci/Micrococci)
Lysostaphin Sensitivity Test - Resistant

A

Micrococci

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13
Q

(Staphylococci/Micrococci)
Modified Oxidase Test/Microdase Test - NEGATIVE

A

Staphylococci

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14
Q

(Staphylococci/Micrococci)
Modified Oxidase Test/Microdase Test - POSITIVE

A

Micrococci

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15
Q

(Staphylococci/Micrococci)
Growth on Furoxone-Tween 80-oil Red O Agar - NEGATIVE

A

Staphylococci

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16
Q

(Staphylococci/Micrococci)
Growth on Furoxone-Tween 80-oil Red O Agar - POSITIVE

A

Micrococci

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17
Q

(Staphylococci/Micrococci)
Aid production from Glycerol (with erythromycin) - POSITIVE

A

Staphylococci

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18
Q

(Staphylococci/Micrococci)
Aid production from Glycerol (with erythromycin) - NEGATIVE

A

Micrococci

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19
Q

(Staphylococci/Micrococci)
OF reaction - Fermenter

A

Staphylococci

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20
Q

(Staphylococci/Micrococci)
OF reaction - Oxidizer

A

Micrococci

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21
Q

true coagulase positive and most virulent species of staphylococci
grow well on most routine media like NA and TSB
on solid media, round, smooth, opaque and butyrous

A

Staphylococcus aureus

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22
Q

on BAP, colonies have golden yellow color and β-haemolytic
responsible for various skin, wound and deep tissue infection

A

Staphylococcus aureus

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23
Q

Staphylococcus aurreus is cultivated by adding

A

7.5 to 10% NaCl—HALOPHILIC

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24
Q

VIRULENCE FACTORS of Staphylococcus Aureus

A

A. Antigenic Structure
B. Enzymes
C. Toxins

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25
Q

contain ribitol teichoic acid in cell wall

A

Teichoic Acid

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26
Q

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

A

Peptidoglycan

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27
Q

group specific antigen unique to S. aureus

prevents antibody-mediated phagocytosis by
PMN—competes for the Fc portion

A

Protein A

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28
Q

component on cell wall responsible for clumping of the whole staphylococci in the presence of plasma

A

Clumping Factor

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29
Q

protects fro phagocytosis

A

Capsular Polysaccharide

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30
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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31
Q

2 types of Coagulase (Staphylocoagulase)

A

Cell-bound Coagulase or Clumping Factor
Unbound or Free Coagulase

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32
Q

bound to the cell wall and clots human, rabbit or pig plasma

A

Cell-bound Coagulase or Clumping Factor

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33
Q

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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34
Q

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

A

Hyaluronidase (Spreading Factor)

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35
Q

fibrinolytic activities by dissolving fibrin clot

A

Staphylokinase (Fibrinolysin)

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36
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 Enzyme)

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37
Q

important in the formation of furuncles, carbuncles and boils

A

Lipase (Fat-splitting Enzyme)

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38
Q

lowers viscosity of exudates giving the pathogen more mobility
destroys DNA

A

Deoxyribonuclease (DNAse) and Phosphatase

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39
Q

breaks down Penicillin and β-lactam drugs

A

β-LACTAMASE

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40
Q

Cytolytic Toxins

A

Hemolysins and Leukocidins

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41
Q

4 types of Hemolysins

A

a. α-Hemolysin
b. β-Hemolysin (Sphingomyelinase C)
c. δ-Hemolysin
d. γ-Hemolysin

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42
Q

damage RBC, platelets and macrophages and cause severe tissue damage
Predominant hemolysin

A

α-Hemolysin

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43
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)

A

β-Hemolysin (Sphingomyelinase C)

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44
Q

exhibited in the CAMP test
lethal and dermonecrotic

A

β-Hemolysin (Sphingomyelinase C)

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45
Q

less toxic to cells than either α-hemolysin or β-hemolysin
produced by all S. aureus strain that cause RBC injury in culture an produce edematous lesions

A

δ-Hemolysin

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46
Q

associated with Panton-Valentine leukocidin (PVL)

A

γ-Hemolysin

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47
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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48
Q

heat-stable exotoxin: 100° C for 30 minutes
resistant to hydrolysis by gastric and jejunal enzymes

A

Enterotoxins

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49
Q

act as neurotoxins that stimulate vomiting through the vagus nerve
produced by 30% to 50% of S. aureus isolates

A

Enterotoxins

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50
Q

Staphylococcal food poisoning

A

Enterotoxins A, B, and D

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51
Q

TSS (Enterotoxins)

A

Enterotoxins B and C and sometimes G and I

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52
Q

Staphylococcal Pseudomembranous
Enterocolitis (contaminated milk products)

A

Enterotoxin B

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53
Q

aka ENTEROTOXIN F or PYROGENIC EXOTOXIN C
menstruating-associated TSS= TSS associated with tampon use
chromosomal-mediated toxin

A

TOXIC SHOCK SYNDROME TOXIN-1(TSST-1)

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54
Q

SUPERANTIGEN stimulating T-cell proliferation and production of a large amount of cytokines
low concentrations= leakage by endothelial cells; higher concentrations= cytotoxic

A

TOXIC SHOCK SYNDROME TOXIN-1(TSST-1)

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55
Q

aka EPIDERMOLYTIC TOXIN A and B or EXFOLIATIN serotypes A and B
Serine protease that divides the intercellular bridges of the epidermis and causes excessive sloughing of the epidermis (stratum granulosum)

A

Exfoliative Toxins

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56
Q

causes STAPHYLOCOCCAL SCALDED SKIN SYNDROME referred to as RITTER’S DISEASE

implicated in BULLOUS IMPETIGO

A

Exfoliative Toxins

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57
Q

mild inflammation of a hair follicle or oil gland; infected area is raised and red

A

Folliculitis

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58
Q

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

A

Furuncles (Boils)

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59
Q

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

A

Carbuncles

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60
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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61
Q

superficial cutaneous infection commonly seen in newborns and young children characterized by the formation of encrusted pustules surrounded by red border

A

Impetigo

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62
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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63
Q

clinical manifestation with multiple causes; symptoms are due to hypersensitivity reaction

A

Toxic Epidermal Necrolysis (TEN)

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64
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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65
Q

intoxication resulting from ingestion of a toxin formed outside the body
symptoms appear rapidly (2 to 8 hours after ingestion) and resolve within 24 to 48 hours: nausea, vomiting, abdominal pain, and severe cramping, diarrhea

A

Food Poisoning

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66
Q

Percentage of Enterotoxins A, D, and B in Food Poisoning

A

Enterotoxins A (78%), D (38%), and B (10%)

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67
Q

perfuse and watery diarrhea due to water and electrolyte loss

A

Food Poisoning

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68
Q

Enterotoxin A and (leukocidins) LukE and LukP

A

Enterocolitis

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69
Q

leads to secondary pneumonia and endocarditis observed among IV drug users

A

Staphylococcal Bacteremia

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70
Q

secondary to bacteremia

A

Staphylococcal Osteomyelitis

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71
Q

secondary to influenza virus infection
multiple abscesses and focal lesions in the pulmonary parenchyma

A

Staphylococcal Pneumonia

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72
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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73
Q

JOINT INFECTIONS/SEPTIC ARTHRITIS

Bacteria in Both Adults and Neonates/ Children

A

S. aureus
S. agalactiae
S. pyogenes
Enterobacteriaceae

74
Q

JOINT INFECTIONS/SEPTIC ARTHRITIS

Bacteria in Neonates / Children Only

A

H. influenzae type b (Hib)
Kingella kingae

75
Q

JOINT INFECTIONS/SEPTIC ARTHRITIS

Bacteria in Sexually Active

A

N. gonorrhoeae

76
Q

Specimen for Laboratory Diagnosis

A

Pus, Purulent Fluids, Sputum, Urine, Blood

77
Q

Laboratory Diagnosis

Gram Stain

A

Gram (+) cocci in irregular clusters

78
Q

Lab Diagnosis - Culture Media

A

BAP, PEA, MSA, CNA, Chapman Stone Agar, Vogel-Johnson
Medium
Columbia Colistin–Nalidixic acid (CNA) -purulent exudates
MSAandPEAheavilycontaminated specimen
CHROMAgarselective-differential for MRSA

79
Q

Lab Diagnosis - Biochemical Test (S. aureus)

A

a. Catalase Test
b. Coagulase Test
c. Mannitol Fermentation Test
d. Growth on Tellurite Glycine Agar
e. Polymyxin B Sensitivity
f. Lysostaphin Sensitivity Test (2ug/mL)
g. Voges-Proskauer (VP) Test
h. Deoxyribonuclease (Dnase) Test
i. Pyrrolidonyl Arylamidase (PYR) Test
j. Rapid Methods of Identification
k. Molecular Methods

80
Q

Aerobic Catalase Test Reagent

81
Q

Anaerobic Catalase Test Reagent

82
Q

Catalase Test RESULT

A

Staphylococcus: catalase +
Streptococcus: catalase -

83
Q

best single criterion of recognition and pathogenicity of S. aureus

A

Coagulase Test

84
Q

Reagent for Coagulase Test

A

Rabbit plasma with EDTA

85
Q

Methods for Coagulase Test

A
  • Slide Method
  • Tube Method
86
Q

rapid screening test
detects cell-bound coagulase or clumping factor

A

Slide Method

87
Q

sensitive but definitive; confirm all slide negative results
detects extracellular or free coagulase

A

Tube Method

88
Q

Other Slide Coagulase Positive:

A

S. lugdunensis and S. schleiferi

89
Q

Other Tube Coagulase Positive:

A

S. hyicus, S. intermedius, S. lutrae, S. delphini and S. schleiferi subsp. coagulans

90
Q

In tube method incubate it for ___________________: if no clot forms after 4 hours reincubate at room temperature for additional ______ hours

A

1-4 hours at 35°C-37°C ; 20 hours

91
Q

In Coagulase Test Result should be read within 4 hours to prevent

A

False (-) Reaction

92
Q

lyses the clot formed

A

FIBRINOLYSIN

93
Q

Coagulase plasma with _____ is not suitable

94
Q

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

A

False (+) Result

95
Q

can ferment mannitol and can tolerate high salt concentrations (7.5-10%)

96
Q

Culture Medium for Mannitol Fermentation Test

A

Mannitol Salt Agar

97
Q

Mannitol Salt Agar
pH indicator:
Positive Result:

A

: Phenol Red

: yellow-colored colonies surrounded by a yellow halo

98
Q

S. aureus reduce tellurite producing what?

A

JET-BLACK COLONIES

99
Q

In Tellurite Glycine Agar, Other Staphylococci is ________

A

inhibited; if growth occurs gray colonies are seen

100
Q

Polymyxin B Sensitivity

A

S. aureus = Resistant
Other Staphylococci = Susceptible

101
Q

Lysostaphin Sensitivity Test (2ug/ml)

A

S. aureus = Sensitive
Micrococci = Resistant

102
Q

differentiate S. aureus (+) from S. intermedius (-)

103
Q

Culture Medium for VP Test

A

VP Broth with 5% glucose

104
Q

Reagent for VP Test

A

α-naphthol and KOH

105
Q

Other VP Positive:

A

S. lugdunensis, S. haemolyticus, and S. schleiferi

106
Q

Culture Medium for Dnase test

A

DNA-Methyl Green Agar

107
Q

T or F
S. aureus = Dnase Negative

A

False; Dnase Positive si S. aureus (like pag nagegets)

108
Q

differentiates coagulase(+) staphylococci by slide method

A

Pyrrolidonyl Arylamidase (PYR) Test

109
Q

Substrate for PYR Test

A

Pyroglutamyl-β-naphthylamide (L-pyrrolidonyl-β-naphthylamide; PYR)

110
Q

Reagent for PYR Test

A

p-dimethylaminocinnamaldehyde

111
Q

End Product for PYR Test

A

L-pyrrolidone and β-naphthylamine

112
Q

Result of PYR Test

A

Cherry Red

113
Q

Positive for PYR Test

A

S. lugdunensis, S. intermedius S. schleiferi, S.
haemolyticus

114
Q

Negative for PYR test

115
Q

Particle Agglutination Test

A

Staphyloslide - use sensitized sheep RBC
Staphaurex
BACTiStaph
Staphylochrome
Sero-STAT
Bacto Staph Latex
Accu-Staph
Hemostaph
Staphylatex

116
Q

plasma-coated carrier particles

117
Q

plasma detects clumping factor with?

A

fibrinogen

118
Q

plasma detects protein A in the cell wall of S. aureus with?

119
Q

identifying both MRSA and MSSA

A

Real-time PCR

120
Q

staphylococci from prepared smears in
blood cultures
identification of mecA gene

A

Qualitative Nucleic Acid Hybridization Assays

121
Q

Specimen for Molecular Methods

A

Anterior Nares Swabs

122
Q

Advantage of Molecular Methods

A

rapid detection test for MRSA

123
Q

indigenous microbiota of the skin
contaminant of medical instruments, catheters, CSF shunts and prosthetic heart valve implants (implanted medical devices), hip prostheses

A

Staphylococcus epidermidis

124
Q

Diseases caused by S. epidermidis

A

Stitch abscess, Health care-acquired UTIs, Endocarditis, Bacteremia

125
Q

adherence of S. epidermidis

A

Poly-γ-DL-Glutamic Acid (PGA)

126
Q

S. epidermidis in BAP

A

gray to white, opaque, small to medium-sized pin heads and non-hemolytic colonies

127
Q

S. epidermidis - Biochemical Tests

A

Coagulase(-),
CNA (+),
DNase (-),
Mannitol Fermentation (-)

128
Q

S. epidermidis is susceptible with

A

5-ug NOVOBIOCIN (16mm-27mm)

129
Q

present on the normal skin and in the periurethral and urethral flora
adheres effectively to the epithelial cells lining the urogenital tract

A

Staphylococcus saprophyticus

130
Q

Disease associated with S. saprophyticus

A

common cause of UTI in young sexually active women
urine culture <10,000 CFU/ml = significant

131
Q

S. saprophyticus in BAP

A

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

132
Q

S. saprophyticus - Biochemical Test

A

Coagulase (-),
Dnase (-)
Mannitol Fermentation (-)

133
Q

Resistance to NOVONIOCIN (5ug; 6mm-12mm) and NALIDIXIC ACID
Absence of Phosphatase production

A

Staphylococcus saprophyticus

134
Q

clumping factor (+), tube coagulase (-)
contain mecA gene that encodes oxacillin resistance
more aggressive than other CoNS in ineffectivity

A

Staphylococcus lugdunensis

135
Q

Disease associated with S. lugdunensis

A

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

136
Q

Other Coagulase-Negative Staphylococci

A

S. warneri, S. capitis, S. simulans, S. hominis, and S. schleiferi
S. haemolyticus

137
Q

causes endocarditis, septicemia, and wound infections

A

S. warneri, S. capitis, S. simulans, S. hominis, and S. schleiferi

138
Q

causes
wounds, bacteremia, endocarditis, and UTIs
medium-sized colonies, with moderate or weak hemolysis and variable pigment production

A

S. haemolyticus

139
Q

NOVOBIOCIN SUSCEPTIBLE CoNS

A

S. epidermidis
S. capitis
S. haemolyticus
S. hominis subsp. hominis
S. lugdunensis
S. saccharolyticus
S. warner

140
Q

NOVOBIOCIN RESISTANT CoNS

A

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

141
Q

RESISTANT GENES PRODUCED BY STAPHYLOCOCCI

A

a. Erythromycin Ribosomal Methylase (ERM) Gene
b. Methionine Sulfoxide Reductase (MSR) A Gene

142
Q

Class of enzyme inactivating genes
Codes for the methylation of the 23s rRNA
Results in resistance to erythromycin
Inducible or constitutive resistance to clindamycin

A

Erythromycin Ribosomal Methylase (ERM) Gene

143
Q

May not bedetected in routine susceptibility testing
Confer cross-resistance to macrolides (erythromycin) and streptogramins (quinupristin)

A

Erythromycin Ribosomal Methylase (ERM) Gene

144
Q

Codes for efflux mechanism resistance to
erythromycin but susceptibility to clindamycin

A

Methionine Sulfoxide Reductase (MSR) A Gene

145
Q

type of S. aureus that is resistant to methicillin, nafcillin, and oxacillin

A

Methicillin-Resistant Staphylococci aureus (MRSA)

146
Q

 acquired after prolonged stay in the hospital, close contact with carriers, effects of broad spectrum antibiotic treatments and exposure to nasal secretions

A

Methicillin-Resistant Staphylococci aureus (MRSA)

147
Q

treatment of choice for MRSA

A

VANCOMYCIN

148
Q

Types of MRSA

A

Community-Associated MRSA (CA-MRSA),
Health Care–Associated Community-Onset (HACO-MRSA),
Hospital-Associated (HA-MRSA)

149
Q

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

150
Q

used to screen for MRSA in clinical samples
differentiate MRSA from hyperproducers of β-lactamase, or Borderline Oxacillin-Resistant Staphylococcus aureus (BORSA)

A

Oxacillin-Salt Agar Plate

151
Q

BORSA

A

Borderline Oxacillin-Resistant Staphylococcus aureus (BORSA)

152
Q

Chromogenic Selective Differential Media

A

MRSA Select
Spectra MRSA
CHROMagar MRSA

153
Q

inhibit non-MRSA

154
Q

Result of Chromogenic Test

A

Changes in color of MRSA colonies within 24 to 48 hours using CHROM Agar against colonies of non-MRSA

155
Q

Mauve-colored colonies

A

Methicillin-Resistant Staphylococci aureus (MRSA)

156
Q

detect altered PBPs
alternative method for testing and confirmation of oxacillin resistance
performed on both CoNS and S. aureus

A

Latex Agglutination

157
Q

“gold standard” for MRSA detection

A

Molecular Nucleic Acid Probes or PCR Amplification

158
Q

Screening for Vancomycin-Resistant Staphylococci

A

Vancomycin Agar Plate

159
Q

= discrepant macrolide test results (erythromycin resistant and clindamycin susceptible)

A

Modified Double Disk Diffusion Test

160
Q

Beta-Lactamase Test

A

a. Cephalosporinase Test
b. Acidimetric Method
c. Iodometric Method

161
Q

uses cephalosporin or cefinase disk

A

Cephalosporinase Test

162
Q

Cephalosporinase Test

Substrate:
(+) result:

A

 Substrate: nitrocefin
 (+) result: deep pink or red color within 10 minutes (60 minutes for Staphylococci)

163
Q

Acidimetric Method
 Reagent:
 pH indicator:
 (+)result:

A

 Reagent: citrate-buffered penicillin
 pH indicator: phenol red
 (+)result: red to yellow (penicilloic acid = decrease pH)

164
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)

165
Q

ANTIMICROBIAL TESTING
-Treatment:

A

methicillin, oxacillin, nafcillin, cloxacillin, and dicloxacillin (penicillinase-resistant penicillin drugs)

166
Q

most commonly used drug

167
Q

Drug for Cutaneous Infections

A

Oral oxacillin or dicloxacillin, if allergic, erythromycin may be substituted

168
Q

Antimicrobial Testing
- Systemic

A

parenteral nafcilllin or oxacillin, if allergic, vancomycin or cephalosporin may be used

169
Q

Antimicrobial Testing
- MRSA

A

vancomcin alone or in a combination with rifampicin

170
Q

Screening Test for MRSA:

A

Oxacillin Screen Plate

171
Q

Culture Media for Oxacillin Screen Plate

A

MHA with 4% NaCl and 6 ug/mL oxacillin
- spot inoculated with cotton swab and incubated for 24 hours at 35°C

172
Q

oxacillin in cation-supplemented MH broth containing 2% NaCl

A

Microdilution Testing

173
Q

Screening Test for MRSA: Oxacillin Screen Plate
Result:
CoNS:

A

Result:
 Resistant- growth of more than one colony
 Susceptible- no growth on the agar plate
CoNS:
 Resistant- 24 mm zone of inhibition
 Susceptible- >25 mm zone of inhibition

174
Q

Disadvantage of Oxacillin

A

Does not reliably detect oxacillin-resistant CoNS

175
Q

preferred method for detection of oxacillin-resistance for both S. aureus and S. lugdunensis
improves detection of MRSA

A

Cefoxitin Disk Diffusion (30 ug)

176
Q

serves to induce greater PBP2a in mecA-containing strains
Test reagent to detect resistance- both MIC and diffusion method

A

Cefoxitin Disk Diffusion (30 ug)

177
Q

Interpretation for Cefoxitin Disk Diffusion

A

Resistant- <21 mm
Susceptible- >22 mm

178
Q

detection of heteroresistant VISA because the test uses a higher concentration of organisms (1 x 108 bacteria/ mL)

A

Macro E Test

179
Q

S. aureus should be screened with 6-ug/mL vancomycin incorporated into BHIA
Broth microdilution test
best method for detection of either Vancomycin-resistant S. aureus (VRSA) or VISA

A

Vancomycin Agar Screen Plate

180
Q

Confirmatory test for oxacillin resistance

A

Broth dilution and E-test

BACTERIOLOGY - LEC (19 decks)

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