Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Infectious diseases > Garlanda 1 > Flashcards

Garlanda 1 Flashcards

1
Q

How can labs id organisms

A

directly (microscopically, culture, genome)

indirectly (finding antibodies to that organism)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are the 5 types of lab tests

A 
microscopy
culture
immunologic tests
nucleic acid based ID
non nuclei acid based ID
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

The 5 I’s of sample processing

A 
inoculation
incubation
isolation
inspection
identification
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What word is most important in inoculation

A

medium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

define culture

A

the visible growth of the microbe in or on the medium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what is the gold standard for ID

A

culture

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

in the isolation stage what are the microbes in

A

colonies on solid media, or turbidity (free floating cells) in broths. Note subculturing occurs here

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How do non nucleic acid tests (NNAT) work

A

they use phenotypic (functional or morphologic) characteristics

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

tests are done in what order

A

sequentially, which the results of the last one helping guide the next one

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

for lesions where should you sample

A

the leading edge

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q 
fill in the collection method for the following locations
skin, membrane
blood
CSF
stomach
urine
lungs
diseased tissue
A 
sterile swab (NYLON)
needle aspiration from vein
needle aspiration from subarachnoid space
intubation
catheter with midstream urine
sputum
surgical removal biopsy
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

contamination of urine sample

A

all non surgical samples become contaminated with urogenital flora during collection. these bacteria witll replicate if the specimen is not quickly stored in a preservation tube at 4C

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

when should you collect samples for blood parasite infections

A

during a febrile episode or every 6 hours for a 24 hour period

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Quantity of CSF culture needed

A

2 ml from tubes 2, 3, or 4

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

For anaerobic culture what are 3 considerations

A
  • you should not obtain sample from areas where normal flora is present
  • fluid specimens (abscess) are superior to swab specimens
  • transport fluid in a syringe or an anaerobic transport vial
  • are best collected with metal (needle aspiration or scapel)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

T/F a large piece of tissue (5-10 mm) willl protect anareobes in the center

A

T

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

How to collect chlamydia/N. gonorrhea culture

A

chlamydia in universal transport medium, GC culture in amies and charcoal or tranport to lab for immediate plating

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

is culture an option for tissue sent in formalin

A

no

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

is bacterial culture possible in sent in viral transport media

A

no, most VTM contain antibiotics

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

when to test for microbiology

A

before giving antibiotics

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Levels of biosafety and examples

A

BSL 1: non pathogenic for healthy ppl. Use soap/disinfectants E.g: non pathogenic E.coli
BSL 2: moderately hazardous. Use safety cabinets. E.g MRSA, heptatitis
BSL 3: use cabinets, rooms with HEPA filters, double doors. E.g. TB, B antracis, yellow fever, SARS/COV2
BSL 4: fatal dx E.g. ebola, smallpox, lassa fever viruses. Use separate building, airlocks, showers, vacuum. Filter air and water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

HEPA (high efficiency particulate air) filters can be placed on

A

safety cabinets, operating rooms, rooms of infected or immunocompromised pts

23
Q

When do you need microscopic examination of tissue in a culture

A

to distinguish invasive disease from surface colonisation

24
Q

Visibility of fungi can be improved by

A

applying 10% KOH to dissolve surrounding skin tissue and non fungal organisms so that you only have the fungus left, and its easier to observe

25
Q

what volume is needed for microscopic detection of microbe

A

1 x 10^4-5/mL (this is why most specimens are concentrated by centrifugation before examination

26
Q

Three kinds of microscopy

A
  • bright field
  • dark field (high contrast, for colorless cells, and pale objects)
  • phase microscopy: for living cells, is high contrast
    this includes differential interference contrast microscope (aka nomarski): for 3D look
27
Q

Dyes used as stains are usually

A

salts

28
Q

chromophore is

A

the colored portion of the dyes

29
Q

acidic dyes stain:
basic dyes stain:
which is more common

A

alkaline structures
acidic structures
basic dyes are more common since most cells are negatively charged

30
Q

examples of simple stains

A

crystal violet, safranin, methylene blue

31
Q

examples of differential stains

A

gram stain, acid fast stain, endospore stain, histological stain (gomori methenamine silver for fungi, and haematoxylins and eosin)

32
Q

acid fast stain work on

A

mycobacteria and nocardia, cryptosporidium (waxy lipids in the cell wall)
THIS NEEDS HEAT ITS V IMPORTANT TO GET THE CARBOFULSHIN DYE INTO THE ACID FAST CELLS
then you use HCL to remove excess carbofulshin
and dye the remaining cells with methylene blue

33
Q

india ink (colloidal carbon stain) is for

A

cryptococcus neofromans and encapsulated fungi, here the background is stained

34
Q

silver stains are used for

A

spirochetes, H pyloris, microsporidia, bartonella henselae (Cat scratch disease)

35
Q

wright stain and giemsa stain are for

A

parasites and intracellular organisms

36
Q

trichrome stain (gomori wheatley stain) and iron hematoxylin stain are for

A

intestinal protozoa.
Gomori is for microsporidia (can miss helminth eggs and larvae, and not great for cryptosporidium)
Iron stains cell inclusions and nuclei. Helminth eggs may stain too dark to permit ID

37
Q

endospore stain (schaeffer-fulton stain) is for

A

clostridum and bacillus (the spore wall will have the green dye (circles))

38
Q

eg of special stains

A
  • negative stain: for capsule, acidic dyes are replused by negative charges on the capsule
  • flagellar stain: important to ID species
39
Q

T/F fluorescent stains allow detection at lower concentration

A

true (<1 x 10 ^4 cells/ml)

40
Q

E.g. of fluorescent stains

A
  • Acridine orange (for bacteria or fungi): binds to nucleic acids. At low ph 3.5-4 they stain bright orange
  • Auramine-rhodamine and Auramine 0 for mycobacteria
  • Calcofluor white for fungi and dermatophytes
41
Q

Define direct or indirect immunofluoresence

A

coupling a fluorescent dye to an antibody directed at a pathogen.
After the dye is covalently linked to an antibody, the dye antibody binds to the antibodies target making the target visible under the light

42
Q

examples of general purpose media for culture

A

blood agar (for culture of fastidious organisms and to differentiate hemolytic organisms), chocolate agar

43
Q

streak plates use a

A

sequential pattern of streaks

44
Q

what is nutrient broth

A

beef extract and peptones in water

45
Q

what is nutrient agar

A

agar 1.5%, complex polysaccharide from cell wall of red algae

46
Q

defined or synthetic media are

A

Is medium where all chemicals used are known, no yeast, plant or animal tissue is present

For Autotrophs: Inorganic salts and a source of CO2
For Chemoheterotrophs: glucose,
amino acids, vitamins
(Fastidious organisms)

47
Q

complex media is

A

Undefined composition. From partial digestion of different protein
sources. E.g. nutrient broth, Trypticase soy agar, MacConkey agar….
Addition of blood: enriched medium.

48
Q

selective media is

A

Media that allows the growth of certain organisms while inhibiting the growth of others

Eosin, methylene blue, crystal violet dyes, bile salts, to inhibit Gram +.

  • NaCl for salt tolerant: S. aureus.
  • Sabouraud dextrose agar, low pH, for fungi (bacteria inhibited).
  • Enrichment culture, or cold enrichment for V. cholerae.
49
Q

differential media is

A

one component is used in a differential manner by diverse
microorganisms.
- BLOOD AGAR: Streptococcus pneumoniae partial digests blood: alpha-hemolysis;
Streptococcus pyogenes completely digests: beta-hemolysis; Enterococcus foecalis
does not digest: gamma-hemolysis.
- PH-SENSITIVE DYE (red to yellow when ph decreases, when specific carbohydrate is metabolised, and gas could be produced)

50
Q

macConkey agar

A

Is for the culture and differentiation of enteric bacteria based on the ability to ferment lactose
(is for gram - bacteria that ferment lactose)
IT IS DIFFERENTIAL MEDIA
S aureus will not grow
E coli will grow (gram neg)
Salmonella enterica will grow yellow

51
Q

anaerobic media is for

A

obligate anaerobes.
Reducing media: Sodium thyglicolate combines with free O2.
Use of anaerobic culture systems
and anaerobic glove box

52
Q

how to do carbohydrate utilization test, and hydrogen sulfide test

A

slide 59

  • H2S: tests for sulfur reducing compunds
  • CO2: tests for ability to ferment a carb, and produce gas
53
Q

chromogenic culture is

A

Culture medium used to isolate, identify, and differentiate specific
microorganism from a heterogeneous population. The medium contains
chromogenic substrate which is utilized by the microorganism to give colored
colonies that is specific for each microorganism. Depending on the color of the
result, the presence or absence of target organism is determined and also
accurately differentiated from others.
Classical culture media are based on the principle of change in color of the pH
indicator, whereas Chromogenic media are based on enzymatic utilization of
chromogenic substrates.
Principle of Chromogenic Media
Chromogenic media contains soluble colorless molecules called
chromogens. Chromogens are composed of two parts: a substrate ( which is the
target of specific enzymatic activity of the microorganism) and a chromophore.
Due to reduced solubility, chromophore forms a precipitate that imparts unique
color to the colony. Depending on the purpose chromogenic media may also
contain inhibitors

Infectious diseases (36 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions