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Micro 425 > Exam 1 > Flashcards

Exam 1 Flashcards

1
Q

List the two Gram+ aerobic cocci:

A

Staphylococcus

Micrococcus

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2
Q

What differentiates S. aureus from S. epi/sap?

A

*S. aureus is Coagulase+ and beta hemolytic

+S.epi/sap are Coagulase- and gamma hemolytic

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3
Q

This media is selective for S. aureus due to what:

A

Mannitol Salt

Due to increased NaCl and lactose fermentation (yellow halo)

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4
Q

T/F Staphylococci spp. are Bacitracin resistant:

A

True

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5
Q

Staphylococci is lysostaphin ______:

A

susceptible

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6
Q

Are Staphylococci spp. microdase + or -?

A

negative (will stay original color)

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7
Q

Describe the Gram stain morphology of Staphylococci spp.:

A

Gram+ grape like clusters (some tetrads and pairs)

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8
Q

T/F Staphylococci are facultative anaerobes:

A

True

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9
Q

What media will Staphylococci spp. grow on:

A

SBAP
Chocolate
Mannitol Salt (selective)

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10
Q

What type of growth will S. epi and S. sap show on Mannitol Salt agar:

A
  • S. epi: growth but no ferment

* S. sap: growth but varied ferment

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11
Q

Which bacteria can cause Ritter disease aka Scalded Skin Syndrome:

A

Staph aureus

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12
Q

Is Staph aureus coagulase+ for bound factor, free factor, or both:

A

Both
Confirmed via tube test
(slide test only shows bound factor)

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13
Q

Gram+, catalase+, coagulase+, medium to large creamy yellow colonies w/ beta hemolysis:

A

Staph aureus

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14
Q

Which bacteria causes tampon related TSS:

A

Staph aureus

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15
Q

What pathologies can Staph aureus cause:

A 
Ritter disease
TSS
Folliculitis, stye, furuncles
Food poisoning
Impetigo
Bacteremia (catheters)
Endocartitis (can be nosocomial)
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16
Q

T/F Endocarditis caused by S. aureus can be nosocomial and mortality rate can reach ~50%:

A

True

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17
Q

Extracellular enzymes and toxins are associated with what bacteria:

A

Staph aureus

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18
Q

This enzyme breaks down fibrinogen into fibrin, and helps protect bacteria from phagocytosis:

A

Coagulase

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19
Q

This enzyme dissolves fibrin/clot, enabling infection to spread:

A

Staphylokinase

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20
Q

These cause lysis of neutrophils and macrophages, inhibiting phagocytosis:

A

Leukocidins

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21
Q

These lyse RBC’s:

A

Hemolysins
(alpha, beta, gamma, delta all lyse RBC’s)
(all but beta may lyse WBC’s)

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22
Q

Which hemolysin does not also lyse WBC’s:

A

Beta

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23
Q

This enzyme hydrolyzes hyaluronic acid in connective tissues, spreading infection:

A

hyaluronidase

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24
Q

Lipase enzymes hydrolyze plasma and skin lipids, enabling organism to colonize this part of the body:

A

Skin (boils, etc)

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25
Q

This enzyme hydrolyzes tissue and are prevalent in Ritter’s Disease:

A

Exfoliatins

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26
Q

These enzymes consist of 7 heat stable proteins:

A

Enterotoxins

A, B, C, C2, D, E, F

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27
Q

Which two enterotoxins are responsible for most food poisoning:

A

A and B

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28
Q

Which enterotoxin is also known as TSST-1 (toxic shock):

A

F

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29
Q

Enterotoxin F is associated with this pathology:

A

TSS

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30
Q

Enterotoxins A and B are associated with this pathology:

A

Food poisoning

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31
Q

This cell wall protein is capable of binding IgG molecules at the Fc/Fab region of B cell receptors, impairing opsonization and phagocytosis:

A

Protein A

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32
Q

What do beta-lactamases do:

A

They are bacterial enzymes that bind to the beta-lactam ring in antibiotics, making them ineffective

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33
Q

Bullous impetigo is associated with this bacteria and will culture ___:

A

S. aureus

positive

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34
Q

What differentiates Staph epi from Staph sap:

A

S. epi: Sensitive to novobiocin

S. sap: Resistant to novobiocin

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35
Q

Which Staph sp is resistant to novobiocin:

A

Staph saprophyticus

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36
Q

Which Staph sp is NOT nosocomial:

A

Staph saprophyticus

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37
Q

This bacteria is known to produce biofilm, causing nosocomial infections w/ prosthetics, etc:

A

Staph epidermidis

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38
Q

This bacteria is the 2nd most common cause of UTI’s in females:

A

Staph saprophyticus

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39
Q

Gram+, Catalase +, Coagulase-, opaque small gray-white colonies, gamma hemolytic, shows growth but NO fermentation of Mannitol salt agar:

A

Staph epidermidis

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40
Q

Gram+, catalase+, coagulase-, bright white creamy colonies, gamma hemolytic, shows growth and varied degrees of fermentation on Mannitol salt agar:

A

Staph saprophyticus

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41
Q

T/F Most coagulase- Staph spp are normal flora; thus are common contaminants in clinical specimens:

A

True

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42
Q

Most frequently encountered coagulase- Staph spp:

A

Staph epidermidis

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43
Q

What imparts wide range of antibiotic resistance to MRSA:

A

mecA gene

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44
Q

What are the two forms of MRSA:

A
  • community acquired

* hospital acquired (nosocomial)

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45
Q

What is the treatment for MRSA:

A

Macrolide antibiotics

clindamyciin or vancomycin

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46
Q

What is used for susceptibility testing of MRSA and why:

A

Oxacillin or Cefotoxin

*because Methicillin is no longer available in US

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47
Q

What media is selective and differential for MRSA:

A

BBL CHROMagar MRSA II

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48
Q

What makes BBL CHROMagar MRSA II selective and differential for MRSA:

A
  • Selective: Cefotoxin (inhibits Gram- and yeasts)

* Differential: Chromagen additives (MRSA hydrolyzes chromagen, producing mauve colonies)

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49
Q

Micrococcus is strictly ______:

A

aerobic

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50
Q

Describe the Gram stain morphology of Micrococcus:

A

Gram+ tetrads

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51
Q

T/F Micrococcus is normal flora of skin, mucosa, oral pharynx, and is common contaminant of clinical specimens:

A

True

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52
Q

T/F Micrococcus is highly pathogenic:

A

False

Is normal flora and common contaminant of clinical specimens

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53
Q

Describe presumptive vs definitive ID of MRSA on BBL CHROMagar:

A
  • Presumptive: mauve colony growth w/in 48

* Definitive: mauve colony growth w/in 24 hours

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54
Q

Micrococcus spp. is bacitracin ____ and lysostaphin _____:

A
  • Bacitracin susceptible

* Lysostaphin resistant

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55
Q

Colonies of this bacteria on SBAP can be white, tan, yellow, golden yellow, orange, pink:

A

Micrococcus spp.

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56
Q

This bacteria is strictly aerobic, appears as Gram+ tetrads, microdase+, is bacitracin susceptible, lysostaphin resistant, and colony color is varied:

A

Micrococcus spp.

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57
Q

List the bacteria included in the group Gram+, Catalase-, Oxidase-:

A 
Streptococcus spp.
Enterococcus spp.
Viridans Strep
Leuconostoc
Aerococcus
Abiotrophia
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58
Q

Gram+ cocci are commonly normal flora of upper respiratory tract, but can be pathogenic in _____:

A

throat

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59
Q

Staph is catalse ___ and Strep is catalase___:

A

Staph: catalase+
Strep: catalase-

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60
Q

T/F Strep pyogenes can be normal flora:

A

False.

All Strep spp EXCEPT S. pyogenes can be normal flora

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61
Q

What is the drug of choice for S. pyogenes, S. agalactieae, and groups C, F, G:

A

Penicillin

if allergy, use erythromycin

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62
Q

Susceptibility testing is indicated for which species of Strep due to resistance:

A

S. pneumoniae

Viridans Strep

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63
Q

The serologrouping based on surface carbohydrate antigens of various Strep species:

A

Lancefield group

A, B, C, D, F, G

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64
Q

Which Lancefield groups are clinically significant:

A

A, B, C, D

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65
Q

What antibiotics are used for susceptibility testing in Strep spp.:

A

Bacitracin

Optochin

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66
Q

Bile solubility test is positive (turns brown) in this Strep sp?

A

S. pneumoniae

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67
Q

Which Gram+, catalase- cocci are PYR positive (turns pink) :

A

Strep pyogenes

Enterococcus sp.

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68
Q

A positive result with this test gives a presumptive ID for Group B strep (agalactieae):

A 
Hippurate hydrolysis
(positive= purple)
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69
Q

The CAMP test is positive in this Gram+, catalase-, aerobic cocci:

A

Strep agalactieae

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70
Q

What can interfere with the CAMP test:

A

CO2 (don’t use a candle jar)

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71
Q

Is Enterococci pos or neg for Salt Tolerance Test:

A

positive

turns yellow or turbid

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72
Q

Is Group D Strep pos or neg for Salt Tolerance Test:

A

negative

stays purple

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73
Q

Describe Gram stain morphology of Strep pyogenes:

A

Gram+ cocci in chains

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74
Q

What would you do to SBAP when culturing a throat swab:

A

inoculate plate with SXT antibiotic to inhibit growth of normal flora

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75
Q

Describe colony morphology of Strep pyogenes on SBAP:

A

gray-white colonies w/ beta hemolysis

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76
Q

What can be a complication of Strep throat in children due to M protein:

A

Glomerulonephritis)

95% recover w/ treatment

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77
Q

Necrotizing fasciitis is associated with this bacteria:

A

Strep pyogenes

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78
Q

TSS with bacteremia and necrotizing fasciitis is associated with this bacteria:

A

Strep pyogenes

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79
Q

List the 4 virulence factors associated with Strep pyogenes:

A

Streptolysin O
Streptolysin S
M protein
SPE’s

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80
Q

Streptolysin O is oxygen_____, Streptolysin S is oxygen_____:

A

O: oxygen LABILE (inactived by O2)
S: oxygen STABLE

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81
Q

Which Streptolysin is antigenic:

A

Streptolysin O is antigenic

induces host immune response w/ antibody production

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82
Q

These virulence factors induce lysis of RBC’s, WBC’s, and platelets:

A

Streptolysins O and S

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83
Q

Which virulence factor of Strep induces antibody formation and may cause disease post-infection:

A

M protein

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84
Q

Which diseases can M protein virulence factor cause post-infection with Strep pyogenes:

A
  • Rheumatic fever (fever, endocarditis)

* Glomerulonephritis

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85
Q

This virulence factor associated with S. pyogenes can induce fevers, inflammation, shock, Scarlet fever:

A

Streptococcal Pyrogenic Exotoxins (SPE’s)

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86
Q

What virulence factors cause Rheumatic Fever and Scarlet Fever:

A
  • Rheumatic: M Protein

* Scarlet: SPE’s

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87
Q

This can occur from S. pyogenes related SPE’s and involves red rash, skin peeling, sore throat, fever:

A

Scarlet Fever

treat w/ 10 day course antibiotics

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88
Q

Which test would be ordered if recent strep infection suspected and experiencing other disease symptoms such as glomerulonephritis:

A

ASO
(anti- streptolysin O)
***will only show if pt had recent strep infection

89
Q

Lancefield grouping is done via this test:

A

latex agglutination

90
Q

Group B strep:

A

Strep agalactieae

91
Q

Which bacteria is associated with respiratory distress, sepsis, pneumonia, meningitis, and death in neonates if mother is not treated:

A

Strep agalactieae

Group B

92
Q

T/F Strep agalactieae is beta hemolytic

A

True

93
Q

Which Strep species are alpha hemolytic:

A 
S. pneumoniae
Strep Viridans (occasionally gamma)
94
Q

This bacteria has small gray colonies resembling donuts:

A

Strep pneumoniae

95
Q

This bacteria is the leading cause of bacterial pneumonia and meningitis:

A

Strep pneumoniae

at risk under 2, over 65

96
Q

PCV13 and PPSV23 are vaccines for what bacteria:

A

Strep pneumoniae

97
Q

Does Strep pneumoniae contain any virulence factors:

A

Yes. C Polysaccharide

impedes phagocytosis

98
Q

S. sanguis, S. mitis, S. gordonii, S. anginosus, and S. mutans belong to this group:

A

Strep Viridans

99
Q

Which species within Strep Viridans is linked to dental caries:

A

Strep mutans

100
Q

Do species within Strep Viridans possess group antigens?

A

No.

101
Q

Are species within Strep Viridans highly pathogenic?

A

No. Low virulence, but maybe cause endocarditis and meningitis.

102
Q

What test differentiates Viridans Strep from Enterococcus and Group D Strep:

A

Bile Esculin

*is negative in Viridans Strep

103
Q

This Gram+, catalase- cocci may display alpha, beta, or gamma hemolysis:

A

Enterococcus spp.

104
Q

Treatment for Enterococcus spp:

A

Vancomycin + aminoglycoside

105
Q

Enterococcus spp is resistant to ____ and ___, and is becoming increasingly resistant to ______:

A

Cephalosporins and Aminoglycosides

Vancomycin (VRE)

106
Q

VRE:

A

Vancomycin Resistant Enterococcus

107
Q

This bacteria used to be named Streptococcus faecalis (Group D Strep), but is now:

A

Enterococcus faecalis

108
Q

T/F Enterococcus spp mostly causes nosocomial UTI’s, but is also a significant cause of endocarditis:

A

True

109
Q

This bacteria is becoming increasingly resistant to Vancomycin:

A

Enterococcus spp.

110
Q

Enterococcus spp is ______ for Salt Tolerance test, PYR test, and Pyruvate broth:

A

Positive

111
Q

What test differentiates E. faecalis (positive) from E. faecium (negative):

A

Pyruvate broth

112
Q

Natural habitat is plants, veggies, dairy:

A

Leuconostoc spp.

113
Q

This bacteria is rarely pathogenic, but can cause meningitis, bacteremia in immunocompromised, also linked to nosocomial outbreak in Spain:

A

Leuconostoc spp.

114
Q

T/F Only some Leuconostoc spp are resistant to Vancomycin:

A

False.

ALL Leuconostoc spp. are Vancomycin resistant.

115
Q

Gram+, Catalase-, PYR-, cocci in chains and pairs, alpha hemolysis, produces CO2 from glucose:

A

Leuconostoc spp.

116
Q

Should Leuconostoc spp. first be considered a contaminant in a clinical specimen?

A

Yes. It is rarely pathogenic.

117
Q

What is the natural habitat of Leuconostoc spp?

A

Plants, veggies, dairy

118
Q

List the 3 organisms for Gram- diplococci, oxidase+:

A

Neisseria meningitidis
Neisseria gonorrhoeae
Moraxella catarrhalis

119
Q

Are there non-pathogenic Neisseria spp that can be normal flora of upper respiratory tract:

A

yes

120
Q

The Gram- diplococci grow best under what conditions:

A

Increased CO2 and humid conditions

121
Q

Is Neisseria meningitidis normal flora?

A

Yes, of oropharyngeal/nasopharyngeal mucous membranes.

122
Q

Presumptive ID of what organism: Gram- diplocci, oxidase+, Strong positive w/ 30% H202:

A

N. meningitidis

123
Q

What is required to make a definitive ID of N. meningitidis:

A

GGAP- and BG-

Must grow on selective agar

124
Q

What is the treatment for Neisseria meningitidis:

A

Broad spectrum antibiotic + corticosteroids

IV penicillin still a possibility, but resistance developing

125
Q

What is the prophylactic treatment for N. meningitidis:

A

Rifampin

126
Q

MCV4 and MPSV4 are vaccines against what organism:

A

N. meningitidis

127
Q

Diptheria protein can be added to a vaccine to do this:

A

Large size will elicit stronger immune response (used for healthy young adults)

128
Q

What media will grow Neisseria meningitidis:

A

SBAP
Chocolate
Modified Thayer-Martin (selective)
Martin Lewis (selective)

129
Q

What should be done with specimens of suspected N. meningitidis:

A

Should be plated immediately to appropriate culture media and transported in CO2 environment

130
Q

Why do you not want to use cotton swabs for gathering bacterial specimen:

A

toxic fatty acids present in cotton– use Dacron swabs instead

131
Q

JEMBEC, Bio-Bag, and Gono-Pack System are all types of what:

A

CO2 transport systems

132
Q

JEMBEC CO2 transport system comes as transport swabs with Amie’s Media w/ charcoal. What is the purpose of the charcoal?

A

Charcoal inhibits toxic fatty acids present in cotton fibers

133
Q

What are the 1st and 2nd causes of bacterial meningitis in the US:

A

1) Strep pneumoniae (pneumococcus)

2) N. meningitidis (meningococcus)

134
Q

What are the mortality rates for N. meningitidis meningitis, treated vs untreated:

A

Mortality rate:
Treated 10%
Untreated 100%

135
Q

What is the syndrome associated with overwhelming bacteremia caused by Neisseria meningitidis:

A

Waterhouse-Friderichsen Syndrome

136
Q

Describe the symptoms of Waterhouse-Friderichsen Syndrome:

A

Bacteremia w/ N. meningitidis
Sudden onset fever, cyanosis, petechiae
Bilateral adrenal hemorrhage, shock
20% mortality rate

137
Q

Bacteria responsible for most cases of newborn meningitis:

A

Strep agalactieae (Group B)

138
Q

Bacteria responsible for most cases of meningitis in infants/children:

A

Strep pneumoniae (pneumococcal)

139
Q

Bacteria responsible for most cases of meningitis in adolescents/young adults:

A

Neisseria meningitidis (meningococcal)

140
Q

Bacteria responsible for most cases of meningitis in older adults:

A

Strep pneumoniae (pneumococcal)

141
Q

Strep pneumoniae is the primary bacteria responsible for causing meningitis in these age groups:

A

Children

Older adults

142
Q

Can people be asymptomatic carriers of Neisseria gonorrhoeae:

A

Yes, but it is NEVER normal flora.

143
Q

Presumptive ID of what bacteria is derived from Gram-, oxidase+ diplococci, glistening non-hemolytic on BAP:

A

Neisseria gonorrhoeae

144
Q

What is required for a definitive ID of N. gonorrhoeae:

A

GGAP+

remember N. meningitidis is GGAP-

145
Q

What are the 1st and 2nd most common STD’s in the US:

A

1) chlamydia

2) gonorrhoeae

146
Q

Where does N. gonorrhoeae infect in males vs females:

A

Males: urethra
Females: cervix

147
Q

Gonococcal opthalmia neonatorum:

A

Occurs in neonates delivered vaginally by N. gonorrhoeae infected mothers; causes blindness

148
Q

Which 3 agar medias are selective for N. gonorrhoeae?

A

Modified Thayer Martin
Martin Lewis
New York City Media

149
Q

Which two medias are selective for both N. gonorrhoeae and N. meningitidis?

A

Modified Thayer Martin

Martin Lewis

150
Q

Does N. gonorrheae require special transport?

A

Yes. It requires a CO2 environment.

JEMBEC, Bio-Bag, Gono-Pack

151
Q

What has to be done to N. gonorrhoeae before Gram staining?

A

Fluids must be centrifuged to concentrate organisms.

152
Q

Why is presence of Gram- diplococci in vaginal secretions NOT dx for N. gonorrhoeae in females?

A

Normal flora of female GI/GU tract can resemble Neisseria spp.

153
Q

What is a definitive ID of N. gonorrhoeae in males?

A

Gram- diplococci inside PMN’s from urethral discharge

154
Q

Why is it important to do an oxidase test on N. gonorrhoeae even though all three Gram- diplococci are oxidase+?

A

Can exclude Neisseria spp. and other oxidase- coccobacilli

155
Q

Medicolegal require this for definitive dx:

A

two forms of ID via combination of tests

156
Q

What is required for presumptive ID of N. gonorrhoeae in sexually active adults:

A

Sample from genital sites

Gram-, oxidase+ diplococci grown on selective media

157
Q

This process differentiates strains of N. gonorrhoeae based on growth with media with different nutrient sources that allow for subtyping (L-proline, etc):

A

Auxotyping

158
Q

Why is auxotyping valuable in N. gonorrhoeae:

A

valuable epidemiological tool, distinguishes between treatment failure vs reinfection

159
Q

How would you distinguish between treatment failure vs reinfection of N. gonorrhoeae of a patient:

A

Auxotyping

160
Q

13 serotypes exist for N. gonorrhoeae, which are the 5 most encountered in the US?

A

A, B, C, Y, W135

161
Q

Which serotypes of N. gonorrhoeae are the most frequent cause of epidemics:

A

Group A and C

162
Q

Serogrouping is achieved via this method:

A

agglutination tests

163
Q

This is a significant pathogen in sputum, can cause otitis media, sinusitis, and pneumonia:

A

M. catarrhalis

164
Q

Gram-, oxidase+, tributyrin hydrolysis+ diplococci:

A

M. catarrhalis

Neisseria spp are tributyrin hydrolysis-

165
Q

This colony can be slide across an SBAP culture plate like a hockey puck:

A

M. catarrhalis

166
Q

T/F Moraxella catarrhalis is normal flora of upper respiratory tract, possibly female genital tract:

A

True

167
Q

Does M. catarrhalis produce beta-lactamase?L

A

Yes, though beta-lactams remain effective.

168
Q

What is used to differentiate M. catarrhalis from Neisseria spp. for a definitive dx:

A

DNase Test Agar

M. catarrhalis is positive = turns green media colorless

169
Q

What phase does exponential bacterial growth occur:

A

Log phase

170
Q

What do prokaryotes have instead of a nucleus?

A
  • Nucleoid containing DNA

* Plasmids containing extrachromosomal DNA

171
Q

What does the cell envelope consist of in Gram positive bacteria:

A
  • Cell wall (pg, teichoic acids)

* cell membrane (encloses cytoplasm)

172
Q

What does the cell envelope consist of in Gram negative bacteria:

A
  • Outer membrane
  • Periplasmic space (pg)
  • cell membrane (encloses cytoplasm)
173
Q

List the 3 cellular appendages:

A

1) capsule
2) fimbriae/pili
3) flagella

174
Q

This is the outermost layer of both Gram+/-, made of polysaccharides, helps bacteria evade immune system and aids in formation of biofilms:

A

Capsule

175
Q

A hardy state that allows bacteria to survive harsh conditions and escape common treatments:

A

endospores

176
Q

List the 4 outcomes of bacterial infection:

A
  • Resolution (return to normal)
  • Restoration of health (w/ lasting effects)
  • Survival (severely compromised)
  • Death
177
Q

What is the goal of the microbiology lab?

A

To tailor treatment via correct microbial identification.

178
Q

Ideally, (but maybe not realistic) all specimens should be transported to the lab within ____ hours of collection:

A

2 hours

179
Q

What is a holding media:

A

Amie’s and Stuart’s

*maintains viability but does not support growth

180
Q

List the special preservatives for each specimen-
Urine:
Stool:
Blood:

A

urine–> Boric acid
stool–> PVA
blood–> anticoagulants (SPS most common)

181
Q

What specimens have priority in the microbiology lab:

A

CSF and blood

182
Q

What stain is used for bacteria that won’t stain well with Gram:

A

Acid Fast

Primary stain is carbolfuchsin

183
Q

What kind of dilution is a 4 phase plate streak:

A

semi-quantitative

grade 1+ to 4+

184
Q

How do you streak for urines:

A

Streak down the middle and then side to side from initial streak. (quantitative method as loops are calibrated)

185
Q

Most bacteria are incubated at this tempL

A

35-37 degrees C

186
Q

These bacteria can grow under aerobic OR anaerobic conditions:

A

facultative anaerobes

187
Q

Chocolate agar-

  • enriched with:
  • heat releases:
  • supports growth of:
  • incubate with:
  • can only detect ___ hemolysis:
A
  • BAP hemolyzed red cells by heat
  • X factor and V factor
  • N. gonorrhoeae
  • CO2
  • alpha
188
Q

PEA agar

  • selective for Gram__ __:
  • inhibits ___ and ___:
  • can be enriched with __ for staph and strep:
A
  • selective for Gram+ cocci
  • inhibits Gram- bacilli and swarming Proteus
  • enriched with sheep blood
189
Q

Modified Thayer-Martin Media is highly selective for ____:

A

N. gonorrhoeae

190
Q

These can be added to Modified Thayer Martin Media for selectivity-

  • Colistin, inhibits____:
  • Vancomycin, inhibits ____:
  • Nystatin, inhibits ____:
  • Trimethoprin, inhibits ___:
A
  • Colistin inhibits gram-
  • Vancomycin inhibits Gram+
  • Nystatin inhibits yeasts
  • Trimethoprim inhibits spreading of Proteus
191
Q

Modified Thayer-Martin Media is enriched with _____ and _____:

A

Chocolate agar + hemoglobin

192
Q

This agar is selective for N. gonorrhoeae, Ureaplasma urealyticum, and Mycoplasma spp.:

A

New York City agar

193
Q

XLD agar is selective and differential for _____ and ____:

A

Salmonella spp. and Shigella spp.

194
Q

XLD agar contains 3 sugars for fermentation differentiation, acid production turns red media this color:

A

yellow

195
Q

How can you tell Salmonella and Shigella apart on XLD agar, since they are both non-fermenters:

A

Salmonella produces hydrogen sulfide, creating black centers of colonies

196
Q

LIM broth is prepared from ___ and ___:

A

Todd Hewitt broth + added antibiotics

197
Q

LIM is a selective enrichment broth to promote growth of this bacteria:

A

Strep agalactiae

198
Q

What is the most widely used enrichment broth in bacteriology:

A

Thioglycollate broth

199
Q

This media contains casein, yeast, beef extracts, vitamins, and an agar supplement to make it semi-solid:

A

Thioglycollate broth

200
Q

What is the purpose of thioglycollate broth being semi-solid:

A

to support growth of anaerobes deep in tube

201
Q

What are the 3 enzyme tests used for Gram+ bacteria:

A

PYR test
Catalase
Coagulase

202
Q

A positive PYR is:

A

disk turns red 5 minutes after addition of PYR reagent

203
Q

A positive catalase test is:

A

bubbling

204
Q

A positive coagulase test is:

A

agglutination

205
Q

A positive PYR test is presumptive ID for ___ and ____:

A

S. pyogenes and Enterococci

206
Q

Catalase test is used to differentiate ___ from ____:

A

Micrococcus (catalase+)

Staphylococci (catalase-)

207
Q

Coagulase test is used to differentiate ____ from ____:

A 
Staph aureus (coagulase+)
other Staph spp. (coagulase-)
208
Q

What 3 enzyme tests are used for Gram- bacteria:

A

Indole
Oxidase
Urease

209
Q

Indole test is used for presumptive ID of ____:

A

E. coli

210
Q

A positive indole test:

A

blue color development

211
Q

This test is used to differentiate among Gram- bacteria:

A

Oxidase

212
Q

Microdase test is a modified oxidase test used to differentiate ____ from _____:

A

Micrococcus (+)

Staphylococcus (-)

213
Q

A positive oxidase test:

A

dark purple

214
Q

Urease test is used to presumptively ID _____:

A

Proteus spp (positive)

215
Q

A positive urea test:

A

slant turns red

216
Q

The % of people in whom the organism is present actually test positive:

A

Sensitivity

217
Q

The % of people without the disease that test negative for the organism:

A

Specificity

218
Q

This media is selective for Staph aureus, differential for S. epi and S. sap:

A

Mannitol Salt Agar

219
Q

What would the test results be for Enterococcus with-
PYR:
Salt Tolerance:
Pyruvate Broth:

A

+
+
+

Micro 425 (12 decks)

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