Bacterial Structure; Gram staining Flashcards

1
Q

Ziehl-Neelsen, Kinyoun, Auramine-Rhodamine, Pappenheim, Baumgarten, Wadefite, Gabett

A

Acid Fast

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2
Q

Neisser’s, Albert’s, Ljubinsky, LAMB (Loeffler’s Alkaline Methylene Blue), Burke’s

A

Metachromatic granules

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3
Q

Dyar, Victoria Blue, Calcofluor white (for Fungal chitin)

A

Cell wall

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4
Q

Levaditi Silver Impregnation, Fontana tribondeau

A

Spirochetes

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5
Q

Dorner’s, Wirtz-Conklin, Schaeffer-Fulton (primary stain is malachite green, mordant is green, decolorizer is tap water, 2nd stain - safranin; Green spore, Pink bacteria)

A

Endospore

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6
Q

Gray’s, Leifson, Caesares Gil, Fisher-Conn

A

Flagella

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7
Q

Anthony’s, Nigrosin, India Ink = negative stain

A

Capsule/Negative stains

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8
Q

Acridine orange, Feulgen

A

Nucleic acid/DNA

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9
Q

Gimenez, Macchiavello

A

Rickettsia

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10
Q

Dienes stain

A

Mycoplasma

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11
Q

McFadyean

A

Bacillus anthracis

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12
Q

Toluidine blue

A

Helicobacter pylori

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13
Q

Wayson’s

A

Bipolar bodies (Y. pestis)

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14
Q

Structure that includes the cell wall, plasma membrane, and other components defining the bacterial surface.

A

Cell Envelope

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15
Q

Bacterial classification basis

A

Cell wall is the primary basis of bacterial classification.

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16
Q

Peptidoglycan layer

A

Composed of N-acetyl-D-glucosamine (NAG) & N-acetyl-D-muramic acid (NAM).

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17
Q

Absence of outer membrane and periplasmic space; thick peptidoglycan; teichoic acid present; 2 basal rings for flagella; resistant to physical destruction.

A

Gram-positive

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18
Q

Presence of outer membrane and periplasmic space; thin peptidoglycan; lipopolysaccharide present; 4 basal rings for flagella; sensitive to physical destruction.

A

Gram-negative

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19
Q

Most important differential staining test in microbiology; stains the microorganism’s cell wall.

A

GRAM STAIN

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20
Q

Most critical step in Gram stain

A

Decolorization.

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21
Q

Primary stain used in Gram staining.

A

Crystal violet

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22
Q

Mordant used in Gram staining.

A

Gram iodine

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23
Q

Alcohol-acetone mixture used in Gram staining.

A

Decolorizer

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24
Q

Counterstain used in Gram staining.

A

Safrinin

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25
Q

Color after 2nd stain (Gram-positive)

A

Purple.

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26
Q

Color after 2nd stain (Gram-negative)

A

Pink.

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27
Q

Overdecolorization, old culture, acidic iodine, B-lactam drugs treatment

A

Gram-positive bacteria may appear Gram-negative.

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28
Q

Underdecolorization, too thick smear

A

Gram-negative bacteria may appear Gram-positive.

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29
Q

Direct smear

A

From specimen.

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30
Q

Indirect smear

A

From culture media.

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31
Q

Smear preparation steps

A

Smear → Air-dry → Fixation (10 mins. at 60°C or 1 min. in 95% methanol).

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32
Q

Direct smear reporting

A

Gram reaction, morphology, arrangement, and other elements seen.

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33
Q

QC Gram-positive

A

Staphylococcus aureus (purple to deep blue).

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34
Q

QC Gram-negative

A

Escherichia coli (pink to deep magenta).

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35
Q

Resists Decolorization

A

Acinetobacter, Kingella, Psychrobacter, Methylobacterium (may appear Gram-positive).

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36
Q

Gram Neutral/Ghost form

A

Bacillus anthracis (ghost capsule), Mycobacteria (poorly stained).

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37
Q

Poorly stained with Gram stain

A

Campylobacter, Brucella, Tropheryma whipplei.

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38
Q

Poorly stained with Safranin

A

Legionella, Gram-negative anaerobes, Francisella.

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39
Q

Not stained

A

Intracellular (Chlamydia, Rickettsia, Ehrlichia, Coxiella), No cell wall (Mycoplasma/Ureaplasma), Spirochetes (Dark-field microscopy).

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40
Q

Quantitating Organisms: None

A

No organism seen.

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41
Q

Quantitating Organisms: Rare

A

1+ <10 on complete smear.

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42
Q

Quantitating Organisms: Few

A

2+ 3–5 per OIF.

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43
Q

Quantitating Organisms: Moderate

A

3+ 6–10 per OIF.

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44
Q

Quantitating Organisms: Many

A

4+ >20 per OIF.

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45
Q

Quantitating Host cells: None

A

No host cells seen.

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46
Q

Quantitating Host cells: Rare

A

1+ <2 per LPF.

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47
Q

Quantitating Host cells: Few

A

2+ 2–10 per LPF.

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48
Q

Quantitating Host cells: Moderate

A

3+ 10–25 per LPF.

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49
Q

Quantitating Host cells: Many

A

4+ >25 per LPF.

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50
Q

Ghost forms

A

Cryptosporidium.

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51
Q

Ghost spherule

A

Coccidioides.

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52
Q

Q Score for Grading Clinical Sample

A

Used to evaluate sample quality based on neutrophil count and squamous epithelial cells.

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53
Q

Q Score 0

A

Average neutrophils: 0; no squamous epithelial cells.

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54
Q

Q Score +1

A

Average neutrophils: 1-9 (few); squamous epithelial cells: -1.

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55
Q

Q Score +2

A

Average neutrophils: 10-24 (moderate); squamous epithelial cells: -2.

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56
Q

Q Score +3

A

Average neutrophils: ≥25 (many/numerous); squamous epithelial cells: -3.

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57
Q

Interpretation of Q Score

A

Higher score indicates better quality of sample; a score of zero means the sample is superficial and not cultured.

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58
Q

Resists Decolorization

A

Acinetobacter, Kingella, Psychrobacter, Methylobacterium (may appear Gram-positive)

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59
Q

Appears as Gram Neutral/Ghost

A

Mycobacteria (Poorly stained)

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60
Q

Poorly stained with Gram stain

A

Campylobacter, Brucella, Tropheryma whipplei

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61
Q

Poorly stained with Safranin

A

Legionella, Gram-negative anaerobes, Francisella

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62
Q

NOT STAINED

A

Intracellular (Chlamydia, Rickettsia, Ehrlichia, Coxiella), No cell wall (Mycoplasma/Ureaplasma), Spirochetes (Dark-field microscopy)

63
Q

Demonstrates presence of Mycolic Acid or Hydroxymethoxy Acid in bacterial cell wall; confirms suspected TB cases if patient is symptomatic or CXR is suggestive

A

Acid Fast Stain

64
Q

SPUTUM Quality Screening Bartlett’s classification

A

<10 epithelial cells, >25 pus cells under LPO

65
Q

DSSM (Direct Sputum Smear Microscopy)

A

2x3 cm smear; 300 OIF examined

66
Q

Present in the cell wall of Mycobacteria

A

Mycolic Acid

67
Q

Ziehl-Neelsen Method (Hot Method)

A

1st Stain: Carbol Fuchsin; Mordant: Heat; Decolorizer: 3% Acid Alcohol; Counterstain: Methylene Blue; Acid-fast: Red/Pink; Non-acid fast: Blue

68
Q

Kinyoun Method (Cold Method)

A

1st Stain: Carbol Fuchsin; Mordant: Phenol/Targetol; Decolorizer: 3% Acid Alcohol; Counterstain: Methylene Blue or Malachite Green; Acid-fast: Red/Pink; Non-acid fast: Green

69
Q

Best Routine AFS Method

A

Ziehl-Neelsen

70
Q

Best Tissue AFS Method

A

Kinyoun

71
Q

Most Sensitive AFS Method

A

Auramine-Rhodamine (read 30 LPF)

72
Q

Auramine-Rhodamine Method

A

1st Stain: Auramine Rhodamine; Decolorizer: 0.5% Acid Alcohol; Acid-fast: Yellow Fluorescence; Non-acid fast: No Fluorescence

73
Q

Auramine-Rhodamine Quenching Agent

A

0.5% KMNO4/Potassium Permanganate

74
Q

3% Acid Alcohol Composition

A

3% HCl and 95% Ethanol

75
Q

AFB Smear Sensitivity

A

20-80%

76
Q

Sensitivity of Acid-fast Stain

A

5,000 – 10,000 AFB/mL

77
Q

Newly Required Number of Sputum Samples for TB Detection

A

2 samples (1 random, 1 early morning sputum)

78
Q

Spot-Spot / Frontloading Method

A

2 samples, one-hour apart: 1 spot-AM & 1 spot-early morning

79
Q

Confirmed Case of Tuberculosis

A

1/2 or 2/2 positive AFB samples

80
Q

CDC AFB Grading - No AFB Seen

A

0 AFB/300 fields

81
Q

CDC AFB Grading - Indeterminate

A

1-2 AFB/300 fields

82
Q

CDC AFB Grading - 1+

A

1-9 AFB/100 fields

83
Q

CDC AFB Grading - 2+

A

1-9 AFB/10 fields

84
Q

CDC AFB Grading - 3+

A

1-9 AFB/field

85
Q

CDC AFB Grading - 4+

A

> 9 AFB/field

86
Q

DOH AFB Grading - 0

A

No AFB/300 fields

87
Q

DOH AFB Grading - +n

A

n AFB/100 fields

88
Q

DOH AFB Grading - 1+

A

10-99 AFB/100 fields

89
Q

DOH AFB Grading - 2+

A

1-10 AFB/field (at least 50 fields)

90
Q

DOH AFB Grading - 3+

A

> 10 AFB/field (at least 20 fields)

91
Q

Fluorescence Issues - Photobleaching

A

Permanent loss of fluorescence due to chemical damage of fluorochrome

92
Q

Fluorescence Issues - Quenching

A

Result of transfer of light energy to nearby molecules such as free radicals, salts of heavy metals, or halogens

93
Q

Staining Methods - Pappenheim’s Staining (Urine)

A

M. smegmatis (Blue) vs M. tuberculosis (Red)

94
Q

Staining Methods - Baumgarten’s Staining (Tissue)

A

M. leprae (Red) vs M. tuberculosis (Blue)

95
Q

Staining Methods - Fite-Faraco Stain

A

Used for M. leprae

96
Q

Modified Acid-Fast Stain

A

Used for partial acid-fast microorganisms like Nocardia, Coccidians (CIC); uses weak decolorizer such as 1% H2SO4 Alcohol

97
Q

Found only in Gram-negative bacteria; Initial barrier to the environment; Composed of Lipopolysaccharide giving negative charge

A

Outer Membrane

98
Q

Permeability barrier; Involved in cell wall synthesis; Site of energy/ATP synthesis (counterpart of mitochondria)

A

Inner Membrane

99
Q

Found only in Gram-negative; Gel-like substance that captures nutrients and detoxifies solutes like antibiotics

A

Periplasm/Periplasmic Space

100
Q

dsDNA

A

Bacterial DNA

101
Q

Extrachromosomal DNA that carries antibiotic resistance genes

A

Plasmid

102
Q

70s in bacteria; 80s in fungi; Responsible for protein synthesis

A

Ribosome

103
Q

Can be removed by boiling (100°C); consists of polysaccharide/carbohydrates (except for B. anthracis) which has Poly-D-glutamic acid/protein; contributes to bacterial colonization and anti-phagocytic properties

A

Capsule

104
Q

Encapsulated bacteria include N. meningitidis, S. pneumoniae, K. pneumoniae, H. influenzae, Cryptococcus neoformans; lab diagnosis via Neufeld Quellung reaction and K or Vi Ag typing

A

Encapsulated Bacteria

105
Q

Food reserve granules that lessen osmotic pressure

A

Metachromatic Granules

106
Q

Babes-Ernst bodies are associated with this bacterium

A

C. diphtheria

107
Q

Bipolar bodies are associated with this bacterium

A

Y. pestis

108
Q

Bacteria that produce many granules, related to this disease

A

M. tuberculosis

109
Q

Bacteria associated with sulfur granules

A

Nocardia

110
Q

Structure for attachment (common pili); also involved in gene transfer (sex pili, F factor)

A

Pili or Fimbriae

111
Q

Bacteria with pili for attachment include N. gonorrhoeae and B. pertussis

A

Pili or Fimbriae (Attachment)

112
Q

Process involving the uptake of naked or free DNA

A

Transformation

113
Q

Gene transfer method involving transposons, plasmids, and a sex pilus

A

Conjugation

114
Q

Gene transfer method involving a bacteriophage (virus)

A

Transduction

115
Q

Structure composed of Calcium dipicolinate, providing resistance to heat, chemicals, nutrient deprivation, and drying

A

Endospore

116
Q

Endospore location for Bacillus anthracis

A

Center

117
Q

Endospore location for Clostridium tetani

A

Terminal

118
Q

Endospore location for Clostridium botulinum

A

Subterminal

119
Q

Structure responsible for locomotion in bacteria

A

Flagella

120
Q

Flagella arrangement where no flagella are present

A

A-trichous

121
Q

Flagella arrangement with a single flagellum at one end of the cell

A

Mono-trichous

122
Q

Flagella arrangement with a single flagellum at both ends of the cell

A

Amphi-trichous

123
Q

Flagella arrangement with a group of flagella located at one end of the cell

A

Lophotrichous

124
Q

Flagella arrangement with multiple flagella around the surface of the cell

A

Peritrichous

125
Q

Flagella composed of an axial filament, used for spirochetes to move in a corkscrew motion

A

Endoflagella

126
Q

Fluid containing thousands of enzymes and the site of protein synthesis in the cell

A

Cytosol

127
Q

Region of the cell containing the bacterial chromosome, which is circular and complexed with RNA

A

Nucleoid

128
Q

Genomic regions where virulence factors are encoded

A

Pathogenicity islands (PAIs)

129
Q

Bacteria involved in biofilm production

A

S. aureus, Streptococcus, Listeria, Pseudomonas, Candida

130
Q

Composition of biofilm

A

Monomicrobic or polymicrobic group of bacteria housed in a complex biochemical matrix

131
Q

Function of biofilm in relation to implants and prosthetic devices

A

Adheres to implants and prosthetic devices; contributes to antibiotic resistance

132
Q

State of cells in a biofilm that are starved, nutrient-deprived, and slow-growing, displaying reduced susceptibility to antimicrobial agents

A

Persister cells

133
Q

Signaling mechanism in Gram-negative bacteria

A

Acyl homoserine lactone (AHL)

134
Q

Signaling mechanism in Gram-positive bacteria

A

Oligopeptides

135
Q

Bacteria known to produce biofilm

A

S. aureus, CONS, Streptococcus, Listeria monocytogenes, P. aeruginosa, Acinetobacter, Aeromonas, Aggregatibacter spp., Salmonella spp., Enterobacter, Enterococcus, Escherichia coli, Klebsiella, Proteus, Serratia, Citrobacter koseri, and Candida albicans

136
Q

Definition of toxins in relation to host cells

A

Biochemically active substances that have particular effects on host cells

137
Q

Exotoxins production

A

Produced by Gram-positive and Gram-negative bacteria

138
Q

Chemical nature of exotoxins

A

Protein

139
Q

Mode of release for exotoxins

A

Secreted

140
Q

Heat stability of exotoxins

A

Destroyed at 100°C

141
Q

Detoxification method for exotoxins

A

Formaldehyde detoxified

142
Q

Immunogenicity of exotoxins

A

Immunologic, convertible to toxoid vaccine

143
Q

Specificity of exotoxins

A

Specific; localized infection

144
Q

Effects of exotoxins on host cells

A

Kills host cells, interferes in cell signals and protein synthesis

145
Q

Endotoxins production

A

Produced by Gram-negative bacteria

146
Q

Chemical nature of endotoxins

A

Protein-lipid-polysaccharide (example: LPS)

147
Q

Release of endotoxins

A

Reacted upon lysis, intact

148
Q

Detoxification of endotoxins

A

Not detoxified

149
Q

Immunogenicity of endotoxins

A

Non-immunologic, not neutralized by antitoxin

150
Q

Specificity of endotoxins

A

Broad; systemic infection

151
Q

Effects of endotoxins on the body

A

Either disrupt or form clots (DIC), fever, activation of complement/immune system, hypotension, shock, death

152
Q

Toxin testing includes

A

Immunodiffusion, PCR, Tissue culture, EIA, RIA, Limulus amebocyte lysate

153
Q

Blood cell that is separated from plasma and lysing them makes a “lysate”, when mixed with endotoxin, it will form clots/precipitates and cause turbidity

A

Horseshoe crab (Limulus polyphemus) - amebocyte

154
Q

For detection of toxins of Clostridium difficile, E. coli O157, and Rotavirus

A

Latex agglutination