lab final Flashcards
1
Q
positive stain
A
stains microorganisms
- basic dyes (cationic) - used more often because have an affinity for nuclear material due to DNA being negatively charged
- crystal violet
2
Q
negative stain
A
stains the background
- acid dyes (anionic) - stain repelled, glass stains
- nigrosin
3
Q
average bacterial cell size
A
0.5-1 um
4
Q
arrangement for rods
A
single, doubles, chains, and palisades
5
Q
arrangement for coccus
A
singles, doubles, tetrads, and clusters
6
Q
gram positive
A
purple cells, low lipid, high peptidoglycan
7
Q
gram negative
A
pink cells, high lipid, low peptidoglycan
8
Q
endospore
A
dormant cell that is resistant to many external conditions
9
Q
bacillus anthracis
A
endospores are used a biological weapon
10
Q
bacillus cereus
A
causes food poisoning
11
Q
clostridium botulinum
A
causes botulism, a form of food poisoning
12
Q
clostridium tetani
A
agent of tetanus
13
Q
clostridium perfringens
A
causes food poisoning, anaerobic wound infections and gas gangrene
14
Q
clostridium difficile
A
causes a severe form of colitis called pseudomembranous colitis
15
Q
environmental factors on microbial growth
A
temperature, nutrient availability, moisture, oxygen, moisture, salinity, osmotic pressure, toxic products, pH.
16
Q
complex medium
A
support a larger variety of microorganism for growth due to adding enrichments
- SBA, brain-heart infusion broth
17
Q
defined medium
A
support growth more for the selection of chemo- & photoautotrophs
18
Q
phases of microbial growth
A
lag - log - stationary - death
19
Q
Direct Count
A
both dead and alive cells
20
Q
turbidimetric method
A
measure turbidity based on absorbance of light in a sample
21
Q
plate count
A
viable cell count
22
Q
plate count
A
CFU/mL
30-300 colony-forming units
23
Q
halophiles
A
salt-loving bacteria
24
Q
selective media
A
selection for a certain type of microbe
25
differential media
visually see the differences of microbial colonies based on metabolic activity
26
issues with heat
sensitivity to heat
- based on environment and genetics
- environmental include - incubation temperature, chemical composition of media, age, concentration
- genetically - thermophiles, thermoduric, heat-resistant endospores
27
heat: dry form
kills by dehydrating, irreversible denaturation. Higher temperatures and more time.
- non-aqueous liquids, glycerin, oils, petroleum jelly, waxes (semi-solids)
- talc and sulphonamides (powders) and glassware
28
heat: moist form kills vegetative and endospores
autoclaving - hot steam and pressure
tyndallization and fractional sterilization steam
29
heat: moist form that only kills vegetative cells
pasteurization - 63 for 30 min, 72 for 15 min
boiling - 10 min to kill pathogens, parasitic worms, & protozoa
30
DNA repair
photoreactivation enzyme (PRE)
- binds to the pyrimidine dimers
31
antibiotics
produced by bacteria or fungi
specific activty
32
disinfectants
non-specific action - protein denaturation, cell membrane damage, cell lysis
used on inanimate objects
33
antiseptics
non-specific action - weaker than disinfectants
used on living tissues
34
test for antibiotic effectiveness
Kirby-Bauer Sensitivity Test Zone of Inhibition
35
staphylococcus species and characteristics
species
- s. aureus (most pathogenic) - Methicillin resistant SA
- S. epidermidis
- S. saprophyticus
gram pos cocci
highly resistant to drying and high pH
36
staph aureus clinical importance
1/3 have in nasal area
minor infections - pimples & boils
major infections - osteomyelitis, pneumonia, endocarditis
37
staph aureus causes
impetigo, scalded skin syndrome, toxic shock syndrome, food poisoning
38
staph aureus factor contributing to virulence
invasion of host skin barriers and immune system
enzymes - catalase, coagulase, hyaluronidase
nucleases, fibrinolysin
39
select for staph and differentiate btw species
staph are halophilic - selective which contains 7.5% NaCl
SBA - S. aureus is b-hemolytic in nature
Coagulase test - produces coagulase
40
mannitol salt agar - selective & differential
selective - staph grows 7.5% NaCl - halophile
diff - s. aureus will ferment mannitol (media red - yellow) and s. epidermidis does not ferment
41
staph biochemical tests
coagulase - presence of enzyme
glucose bromcresol purple slant - ferment glucose
thioglycolate media - require O2 (facultative)
42
strepto and entero
coupled together - Lancefield groups
- specific carb in cell wall
43
utilization of SBA
beta - complete lysis
alpha - partial lysis
gamma - no lysis
enriched - presence of blood
differential - hemolytic activity
44
group A - S. pyogenes - b hemolytic causes
strep throat
skin infections
scarlet fever
toxic shock syndrome
facilitis
rheumatic fever
45
group D - entero (found, resistant, causes, characteristics)
found in intestinal tract, many species are highly resistant to antimicrobials
causes UTI, wound infections, endocarditis
6.5% salt, resistant to bile (bile esculin pos)
46
biochemical test - stept group b & d
CAMP test - group B
bible esculin - group d
6.5% NaCl - group d
47
grams stain results of staph, strep, and entero
staph - gram positive cocci in clusters
strepto & entero - gram positive cocci in chains
48
catalase test for staph/strep
staph - positive for catalase
strept - negative for catalase
49
identification of enteric gram-neg rods
enteric normal biota helps prevent pathogen infection
primary - cause infection (salmonella, e. coli)
opportunitistic - non-pathogenic (psuedomonas is)
50
enteric bacteria cause
UTIs, toxin-mediated infection, traveler's diarrhea, pneumonia, food infection (salmonella, shigella)
51
fermentation broths (G,S,L)
ability to ferment diff sugars, producing acid (low pH), test for production in gas in durham tube
indicator - phenol red
52
methyl red test
tests for mixed acid fermentation of glucose which produces lactic, formic, and acetic acids
indicator - methyl red
positive - red
negative - yellow
53
voges-proskauer test
tests for fermentation of glucose and production of acetoin.
positive - red wine
neg - brown
54
indole test
ability to degrade the AA, tryptophan into indole
indicator - kovac's reagent
positive - pink/red ring
negative - yellow ring
55
citrate test
ability to use citrate as a carbon source, creation of alkaline products (high pH)
indicator - bromothymol blue
positive - blue
negative - green
56
urease test
ability to hydrolyze ure to ammonia & CO2
indicator - phenol red
positive - pink
negative - orange
57
motility test
detects presence of flagellum
positive - fuzzy growth
negative - straight line
58
phenylalanine deaminase test
presence of _____ enzyme
positive - greenish blue
negative - clear
59
XLD agar
selective - inhibits gram pos
differential - ferment of xylose, hydrogen sulfide production
salmonella - red colonies w/ black centers
shigella - red colonies
coliforms - yellow/orange
60
EMB agar
selective - inhibits gram pos
differential -
- non-lactose fermenters - pink
- weak lactose - purple
- strong - green metallic
61
o2 requirements - thioglycollate test
obligate aerobe - require O2
obligate anaerobe - does not require O2
aerotolerant anaerobe - withstand O2
facultative anaerobe - grow in presence/absence
microaerophile - grows in minimal O2
62
GYE agar
selective for actinomycetes
63
TSA agar
selective for bacteria
64
sabouraud's dextrose agar
selective for fungi
65
nitrogen fixation
converts atmospheric N into ammonia which plants can used to build proteins and nucleic acids
66
rhizosphere
soil surrounding plant roots
plant & microorganism - symbiotic relationship
67
actinomycetes
gram pos branching bacteria; decomp & early smell, unicellular, produce antibiotics
68
food intoxication
s. aureus - caused by toxins, no fever
69
mycytoxicosis
intoxication caused by fungal toxins
hallucinogens, carcinogens, liver toxins
70
toxin-mediated infection
e. coli
low fever, bloody diarrhea, kidney failure
71
food infection
salmonella
microorganism multiplies
72
PEA agar
inhibits gram negatives
73
antigen
foreign protein to the host
74
antibody
produced by plasma b cells
fab region - binds specific to AA sequence on antigen
Fc region
75
serology
study of antigen-antibody reaction in vitro (lab)
76
ELISA
enzyme-linked immunosorbent assay
- detect and measure the presence of antigens and antibodies
