Micro Introduction Flashcards
1
Q
Bacterial morphology:
Spherical shaped and can appear singular or in pairs, chains, or clusters
A
Cocci
2
Q
Bacterial morphology:
Rod shaped and can appear singular or in chains
A
bacillus
pl. bacilli
AKA rods
3
Q
Bacterial morphology:
very short rods
A
coccobacilli
4
Q
Bacterial morphology:
very long rods
A
Filamentous
5
Q
Bacterial morphology:
tapered, pointed ends
A
Fusiform bacilli
6
Q
Bacterial morphology:
Multiple shapes. The same organism may exhibit short rods, very long rods, or a variety of other shapes
A
Pleomorphic rods
7
Q
Bacterial morphology:
helical shaped
A
Spirochetes
8
Q
What are the reagents used in a gram stain?
A
- Crystal violet
- Gram’s iodine
- Acetone-alcohol decolorizer (usually 1:1; acetone: 95% ethanol)
- Safranin
9
Q
If a organism stains purple/blue with the Gram stain, it is considered:
Positive
or
Negative
A
Positive
10
Q
If a organism stains pink/red with the Gram stain, it is considered:
Positive
or
Negative
A
Negative
11
Q
Identify the morphology:
A
Diplococci
12
Q
Identify the morphology:
A
Bacilli
(streptobacilli)
13
Q
Identify the morphology:
A
Coccobacilli
14
Q
Identify the morphology:
A
Filamentous rod
15
Q
Identify the morphology:
A
Fusiform rods
16
Q
Identify the morphology:
A
Bacilli
(paslisade)
17
Q
Identify the morphology:
A
Spirochete
18
Q
What part of the bacterial structure causes the bacteria to keep the purple/blue color?
A
Peptidoglycan layer
-A thick peptidoglycan layer makes it more difficult to decolorize all of the crystal violet/iodine complex
19
Q
During a gram stain, the decolorizer dissolves which part of the bacterial structure on gram negative microorganisms removing the crystal violet-iodine complex?
A
Phospholipid layer
20
Q
Why do we heat fix smear?
(3)
A
- Kills bacteria on slide
- Prevents bacteria from washing off the slide
- Smear takes up stain better
21
Q
How long is Crystal violet left on the slide?
A
30-60 seconds
22
Q
How long is iodine left on the gram stain slide?
A
30-60 seconds
23
Q
What is the most important step in the Gram stain process? Why?
A
Decolorization
-Smears can be over- or under-decolorized
24
Q
How long is safranin left on the slide?
A
30-60 seconds
25
Gram stains are always viewed under the microscope using what magnification?
100x oil immersion
26
Human cells should ALWAYS stain which color with Gram stain?
Pink
27
If human cells and bacteria appear washed out and gram positive bacteria appear negative or partially stained, what happend during the staining process?
Over-decolorization
28
If human cells appear dark red-purple and gram negative bacteria appear gram positive, what happened during the Gram staining process?
Under-decolorization
29
Doing what during fixation may distort cell morphology?
Overheating
30
Identify bacteria - CSF
Gram positive diplococci
31
Identify bacteria - Body Fluid
Gram positive cocci
| (streptococcus)
32
Identify bacteria - Bone culture
Gram positive cocci
33
Identify bacteria - Blood culture
Gram positive bacilli palisade arrangement
34
Identify bacteria - Blood culture
Gram positive bacilli
35
Identify bacteria - Blood culture
Gram negative bacilli
36
Identify bacteria - Blood culture
Gram positive cocci
37
Identify bacteria - Abscess
Gram negative bacilli (pleomorphic)
AKA
Coccobacilli
38
Identify bacteria - Genital
Gram negative diplococci
39
At what temperature does polysaccharide melt?
100 C
40
Polysaccharide will stay liquid until what range of temperatures?
45-50 C
41
What is the most basic growth media for bacteria?
Nutrient media
42
Which media grows most organisms that do not have specific nutritional requirements?
Nutrient media
43
Supplemented media with various substances to encourage growth of fastidious organisms
Enriched media
44
What are 2 examples of enriched media often used in the clinical laboratory?
Blood Agar (BA or BAP)
&
Chocolate Agar (CHOC)
45
What is the most common type of blood agar?
Sheep blood
46
\_\_\_\_\_\_\_\_ is only able to be determined on blood agar plates
Hemolysis
47
What is the main difference between CHOC and BA agar?
In chocolate agar, the red cells have been lysed
48
Examples of this type of media include Gram-Negative and Selenite which are used to isolate *Salmonella* and *Shigella* from fecal specimens.
Enrichment broth
49
Enriched media such as BA and CHOC are also known as _________ media because they have no antimicrobial substances and all growth of most organisms
Nonselective media
50
This type of media contains antimicrobial substances to allow growth of specific bacteria while inhibiting the growth of others
Selective media
51
PEA agar and CNA agar are selective media used to grow what specific bacteria?
Gram positive bacteria
52
MacConkey agar and EMB agar are examples of selective media used to grow which type of bacteria?
Gram Negative bacteria
53
What is in PEA agar?
Blood and Phenylethyl Alcohol
54
What is in CNA agar?
Blood and **_C_**olistin and **_N_**alidixic **_A_**cid
55
What does MacConkey agar contain?
Bile salts and crystal violet dye
56
What does EMB agar contain?
Dyes Eosin Y and Methylene Blue
57
This media type is used to distinguish metabolic differences between organisms
Differential media
58
This agar is nonselective (grows most microorganisms), is enriched (grows fastidious microorganisms), and is used for differential (hemolysis).
Blood Agar
59
This agar is selective by growing gram-negative bacilli and can be used for differential (lactose fermentation)
MacConkey agar
| (also EMB agar)
60
Enriched media that grows fastidious microorganisms and is selective for *Neisseria gonorrhoeae*
Modified Thayer-Martin Agar (MTM)
61
Most cultures are incubated at this temperature (Body temp)
35 - 37 C
62
This is considered room temperature
22 - 25 C
63
This incubation temperature is typically used to isolate *Yersinia enterocolitica*
Room temperature
22 - 25 C
64
Temperature at which *Campylobacter jejuni* typically grows
42 C
65
This type of atmosphere is when oxygen is required for growth (21% O2)
Aerobic
66
Type of atmosphere that requires no oxygen
Anaerobic
67
What are microorganisms that can grow in both aerobic and anaerobic conditions known as?
Facultative anaerobes
68
Atmospheric condition in which oxygen is decreased to 5-10% O2
Microaerophilic
69
Atmospheric condition in which carbon dioxide is increased to 5-10% CO2 using either CO2 incubators or candle jars
Capnophilic
70
Atmospheric condition where humidity is increased to 70-80%
Humidophilic
71
Growth interpretation:
Few, sparse, or light growth
Has what grading?
1+
72
Growth interpretation:
Moderate
Has what grading?
2+
73
Growth interpretation:
Many or heavy growth
Has what grading?
3+
74
*Pseudomonas aeruginosa* tends to grow best with normal oxygen levels (21%) this would classify it as liking what type of atmosphere?
Aerobic
75
In order to grow *Clostridium perfringens* a GasPak is utilized to create this type environment
Anaerobic
76
Staphylococcus aureus can grow in both aerobic and anaerobic conditions classifying it as what type of microorganism?
Facultative anaerobe
77
*Campylobacter jejuni* tends to grow best in decreased oxygen conditions (5-10%) this is known as what type of condition?
Microaerophilic
78
*Haemophilus influenza* tends to grow best in increased carbon dioxide (5-10% CO2)
What is this type of condition best known as?
Capnophilic
79
*Haemophilus ducreyi* prefers which type of atmospheric condition?
Humidophilic
| (70-80% humidity)
80
Which type of hemolysis is known as incomplete and looks army green around/underneath colonies?
Alpha hemolysis
81
Which hemolysis is known as complete hemolysis and is clear around/underneath colonies?
Beta hemolysis
82
What is the term for no hemolysis around/underneath colonies on blood agar plates?
Gamma hemoloysis
83
What are the proteins called that produce hemoloysis?
Hemolysins
84
TRUE or FALSE
You can grade hemolysis on any agar plate
False - blood agar plate only
85
What is alpha prime hemolysis?
Beta hemolysis surrounded by Alpha hemolysis
86
What type of hemolysis?
Alpha hemolysis
87
Type of hemolysis
Beta hemolysis
88
Type of hemolysis?
Gamma hemolysis
89
Type of hemolysis?
Alpha Prime hemolysis
90
This type of sterilization technique burns and physically destroys microorganisms
Incinerating
91
This type of sterilization technique kills all microorganisms (3 - 30 minute intervals)
Intermittent boiling
92
This sterilization technique uses steam under pressure (15 psi at 121C for 15 minutes)
Autoclaving
93
What are the specifications for autoclaving? (psi, time, temperature)
15 psi
15 minutes
121 C
94
Sterilization technique that uses a hot oven set to 160 C for 2 hours
Dry heat
95
Sterilization technique that destroys and distorts microorganisms nucleic acids using UV lamps, Gamma radiation, or Electron beam radiation
Irradiation
96
Sterilization technique that physically removed bacterial cells from liquids, gases, and air (ex. HEPA filters)
Filtration
97
Which biosafety level is considered the highest risk?
Biosafety Level 4
98
What BSL?
Microorganisms do not cause disease for normal healthy adults
BSL-1
99
What BSL?
Microorganisms most commonly seen in clinical specimens
Microorganisms not transmitted by inhalation
BSL-2
100
What BSL?
Indigenous or exotic microorganisms
Microorganisms are transmitted by inhalation
BSL-3
101
What BSL?
Dangerous and exotic microorganisms
High risk of aerosol-transmitted infections
BSL-4
102
All of the following are typical practices for BSL-1 EXCEPT:
- Standard precautions
- Aseptic technique
- Handwashing
- PPE (as needed)
- Bench disinfecting
- Work on open bench
- Decontaminate materials
-Decontaminate materials
| (This starts with BSL-2)
103
All of the following are typical practices for BSL-2 EXCEPT:
- All BSL-1 practices
- Limited access to laboratory
- PPE
- Class II Biological safety cabinet (BSC)
- Decontaminate materials
- Laboratories under surveillance
-Laboratories under surveillance
| (This typically starts at BSL-3)
104
All of the following are practices for BSL-3 EXCEPT:
- BSL-2 practices
- Laboratories under surveillance
- Negative pressure in lab
- Respirators required at all times
- Restricted and controlled access
-Respirators required at all times
| (Respirators may be required but not at all times)
105
All of the following are practices for BSL-4 EXCEPT:
- BSL-3 practices
- Take a shower after leaving the lab
- Change clothes before entering the lab
- Decontaminate all materials
- Class II BSC or positive air pressure suit
-Class II BSC or positive air pressure suit
A class III BSC is required for BSL-4
106
TRUE or FALSE:
A BSL-4 lab has dedicated air supply, exhaust, and decontamination systems
TRUE
107
An organism is said to be an ___________ pathogen when it can cause disease in compromised patients
Opportunistic pathogen
108
Microorganisms which can cause disease in healthy individuals are known as \_\_\_\_\_\_\_\_\_\_
Pathogens
109
Term for the pathogenicity of a bacteria
Virulence
110
What types of alcohols can be used for disinfection? (2)
Ethyl
or
Isopropyl alcohol (60-90%)
111
What are the 5 categories of chemical agents that can be used as disinfectants?
1. Alcohols (ethyl or isopropyl)
2. Aldehydes (glutaraldehyde)
3. Phenolics (chemically modified phenols)
4. Quaternary ammonium compounds ("quats")
5. Halogens (bleach and iodophores)
112
What type of human-microbe interactions:
- Human and microbe benefit
- Intestinal bacteria obtain nutrients from ingested food; some organisms produce vitamin K which is used by humans
Mutualism
113
What type of human-microbe interaction:
- Microbe benefits while human is unaffected
- Normal flora organisms are often this type
Commensalism
114
What type of human-microbe interaction:
- Microbe benefits at the expense of the human host
- Examples: disease causing organisms (Group A streptococci)
Parasitism
115
Term for an individual infected with an organism which can be transmitted to another person. Usually asymptomatic.
Carrier
116
Term for an animal infectious disease transmitted to humans
Zoonosis
117
Term for protein toxins that are released from viable bacteria
Exotoxins
118
What do exotoxins do to human cells?
Inhibit protein synthesis in human cells
Harm host cells by damaging the membrane or by interfering with normal metabolic functions.
119
Term for protein toxins that are released upon bacterial lysis
-found in gram negative bacteria only
Endotoxins
120
What do endotoxins tend to do?
Can cause fever, shock, bleeding, and death
121
What is the name of the toxin contained in the lipopolysaccharide of gram negative cell wall?
Lipid A
122
Trypticase soy broth is an example of what type of agar?
Nutrient agar
123
Gram-Negative (GN), Selenite, LIM, and Trans-Vag are all examples of what type media?
Enrichment broths
124
This media type contain antimicrobial substances (ex. dyes, antibiotics, and certain chemicals) Examples include PEA and CNA agar
Selective media
125
This type of media does not contain antimicrobial substances and allows growth of many organisms. Examples include BAP and CHOC.
Nonselective media
126
This type of media allows organisms to be distinguised by metabolic differences. Examples include carbohydrate fermentation media and enteric media
Differential media
127
What is another term you may hear for microaerobic?
Microaerophilic
128
Which selective medium is used for the isolation of Gram-positive microorganisms?
a. Columbia CNA with 5% sheep blood
b. Eosin methylene blue
c. Modified Thayer-Martin
d. Trypicase soy agar with 5% sheep blood
a. Columbia CNA with 5% sheep blood
129
Which selective medium is used for the isolation of Gram-negative microorganisms?
a. Trypticase soy agar with 5% sheep blood
b. Modified Thayer-Martin
c. Eosin methylene blue
d. Columbia CNA with 5% sheep blood
c. Eosin methylene blue
130
A technician notes that the nuclei of all the nutrophils of a sputum gram stain are staining dark blue. What would be the best explanation for this finding?
a. Sputum smear was prepared too thin
b. Cellular components have stained as expected
c. Iodine was omitted from the staining procedure
d. Slide was inadequately decolorized with acetone/alcohol
d. Slide was inadequately decolorized with acetone/alcohol
131
What medium aids in the presumptive identification of organisms based on their appearance?
a. Enriched
b. Selective
c. Specialized
d. Differential
d. Differential
132
TRUE or FALSE
Organisms transmitted through aerosols belong in biosafety level 2 and above
FALSE
Biosafety level _3_ and above
