Flashcards in Bacte Lec - AST Deck (112):
1
challenging a bacteria on what antibiotic they are susceptible or resistant
antimicrobial susceptibility testing
2
determines best antibiotic to be prescribed by doctors
antimicrobial susceptibility testing
3
3 stages of antimicrobial susceptibility testing
1) culture and sensitivity
2) isolation and identification of causative agent
3) susceptibility & resistance to antimicrobial agents
4
suspected organisms in urine sample
Providencia
Escherichia coli
Klebsiella
5
agar for Escherichia coli
Gram negative
EMB/MacConkey
6
Culture media commonly used for urine sample
MacConkey Agar
Eosin Methylene Blue Agar
CAP - not commonly used
BAP
7
CM for Staphylococcus saprophyticus
Blood Agar
8
CM for Gram negative cocci
Chocolate Agar
9
usual causative agent of UTI
Gram negative enteric
10
streaking pattern for culture of urine
clock method
11
heavy infection meaning
UTI
12
light infection meaning
only caused by normal flora
13
yellowing slant and butt meaning
organism is a lactose fermenter
14
with gas formation meaning
organism: Escherichia coli or enterobacter
15
broth for indole testing
tryptone broth
16
cm for indole testing, motility, h2s production
SIM
17
cm for assessing capability of utilizing citrate
simmon citrate agar
18
cm for assessing capability of producing acid/alkali (aceto___) based on carbohydrate fermentation
Methyl Red Voges Proskauer Medium
19
duration of C/S
3-5 DAYS
20
produced by microorganisms, inhibit growth of other microorganisms
antibiotics
21
destroy microorganisms through inihibiting their development or action
antimicrobial agents
22
mold with antibiotic activity
Penicillin notatum or Penicillin chrysogenum
23
means bacteria is capable of producing secondary metabolites which can inhibit growth of other bacteria
zone of inhibition/clear zone
24
which phase of bacterial growth curve shows symptoms
log phase
25
which phase of bacterial growth curve represents the bacteria still adjusting, just inoculated, synthesizing enzymes
lag phase
26
During this phase, the microorganisms are in a rapidly growing and dividing state.
log phase
27
During this phase, cells undergoing division is equal to the number of cell death, and finally bacterium stops its division completely
stationary phase
28
During this phase, the individual is feeling better
stationary phase
29
during this phase, the number of dead cells exceeds the number of live cells.
decline phase
30
RIP
Rifampicin, Isoniazid, Pyrizanamide
31
classif of antibiotic
specific attack
limited spectrum of action
narrow spectrum
32
examples of narrow spectrum antibiotic
vancomycin
penicillin
33
narrow spectrum antibiotic - effective against Gram +
PENICILLIN
34
narrow spectrum antibiotic- effective against Gram + ESP S. aureus
Vancomycin
35
classif of antibiotic
against Gram positive and gram negative
broad spectrum
36
disadvantage of broad spectrum antibiotic
may inhibit normal flora
37
examples of broad spectrum antibiotic
tetracycline, chloramphenicol, azithromax, augmentin
38
type of antibiotic not prescribed when C/S is already performed
broad spectrum antibiotic
39
result of primary infection
superinfection
40
superinfection of these 3 sites is difficult to treat
mouth, Respiratory tract, GUT,
41
Common agents of superinfection
Staphylococcus aureus
Candida albicans
Trichomonas vaginalis
Pseudomonas aeruginosa
42
classif of resistance to antimicrobial agents
before abuse
intrinsic resistance
43
Staphylococcus saprophyticus is resistant to
novobiocin
44
genus resistant to polymyxin
Proteus, Providencia, Morganella, Edwardsiella
45
classif of resistance to antimicrobial agents
may result from chromosomal mutations or from plasmid
acquired resistance
46
classif of resistance to antimicrobial agents
necessitates prior exposure to antimicrobial agent
acquired resistance
47
mechanisms of resistance [4]
modification of the target site
inactivation of antimicrobial agent
decreased permeability of cell wall
alteration of binding or ribosomes
48
mechanisms of resistance
antibiotic's ability to bind to cell wall or ribosome is altered
modification of the target site
49
mechanisms of resistance
bacterial enzymes convert the active drug into inactive form
inactivation of antimicrobial agent
50
mechanisms of resistance
poor entry of antibiotic into bacterial cell wall
decreased permeability of cell wall
51
mechanisms of resistance
resistance of pseudomonas to certain aminoglycosides
alteration of binding of ribosomes
52
protein synthesis inhibition
bacteriostatic or bactericidal
bacteriostatic
53
cell wall synthesis inhibition
bacteriostatic or bactericidal
bactericidal
54
inhibition of cell wall synthesis
penicillin
ampicillin
methicillin
carbenicillin
vancomycin
cephalosporin
55
interference with protein synthesis at 30S ribosomal subunit [7]
gentamicin
amikacin
neomycin
tobramycin
tetracycline
spectinomycin
streptomycin
56
interference with protein synthesis at 50S ribosomal subunit
chloramphenicol
57
competitive inhibition of folic acid synthesis
sulfonmethoxazole
trimethoprim-sulfamethoxazole
58
zones of inhibition measured by [2]
ruler or caliper
59
when can clinicians increase dose of drug
when the organism is found to be moderately susceptible to drug
60
indicator of relative susceptibility
DIAMETER of zone of inhibition
61
principle of kirby bauer disk diffusion method
diffusion
62
relationship between diameter of zone of inhibition and logarithm of MIC antibiotic
INVERSE LINEAR
63
lowest concentration of antibiotic that inhibits in vitro bacterial growth
minimum inhibitory concentration
64
highest dilution of antibiotic that inhibits in vitro bacterial growth
minimum inhibitory concentration
65
dilution factor
total volume/ amount of solute
66
indicates presence of growth
turbidity
67
well-defined chemical composition
medium
68
composition of medium for AST must be [2]
reproducible
constant
69
parameters in AST
Medium - MHA
Agar depth
pH
Density of inoculum
Barium sulfate
70
composition of MHA [6]
Beef infusions
Nucleic acids
vitamins
casein hydrolysate [peptone source]
agar [solidifying agent]
cornstarch [neutralize fatty acids]
71
for fastidious bacteria, MHA is supplemented with
blood
72
increased Ca and Mg, effect to Aminoglycosides
decreased activity of AG against Pseudomonas aeruginosa
73
increased Ca and Mg, effect to tetracycline
decreased activity against all bacteria
74
decreased Ca and Mg, effect to Aminoglycosides
inc activity of AG against Pseudomonas aeruginosa
75
decreased Ca and Mg, effect to tetracycline
inc activity against all bacteria
76
pH for AST
7.2 TO 7.4
77
High pH levels (basic), effect
inc activity of aminoglycosides, erythromycin, clindamycin
78
Low pH levels (acidic), effect
dec activity of aminoglycosides, erythromycin, clindamycin
79
High pH levels (basic), effect to zone of inhibition
false susceptibility/ wider zone of inhibition
80
Low pH levels (acidic), effect to ZoI
false RESISTANCE/ narrow zone of inhibition
81
High pH levels (basic), effect to tetracycline
dec activity
82
Low pH levels (acidic), effect to tetracycline
inc activity
83
agar depth
4 mm
84
thick agar depth meaning
false resistant
85
thin agar depth meaning
false susceptible
86
composition of mcfarland standard
1% BaCl2 and 1% H2SO4
87
Standard cell density
1x10^8 CFU/mL
88
The higher the mcfarland standard, ___ turbid
higher/greater
89
too light (turbdidity)
false susceptible
90
too heavy
false resistant
91
susbtitute to mcfarland
spectrophotometer
92
wavelength for turbidity
600 nm
93
streaking pattern
overlapping method
94
used to fish out bacteria from pure young culture
STERILE cotton swab
95
after inoculation to MHA, allow it to stand for ___ before placing disks
3-5 min not longer than 15 min
96
after inoculation to MHA, allow it to stand for 3-5 before placing disks so as
allow absorption of excess moisture
97
within __ min, disks are applied firmly on MHA
15
98
how many disks can a plate 150 mm diameter accommodate
12 disks 8 outer ring, 4 center
99
in storing antibiotic disks, what type of freezer/ref be used
frost-free
100
antibiotic disks and disk dispensers kept with ___ to prevent deterioration
dessicant
101
to minimize condensation, should be adjusted to
room temp [antibiotic disk]
102
temp for long storage of antibiotic disk
14C below in a non-frost freezer
103
temp for working supply of antibiotic disk
2-8C
104
Incubation
temp
hrs
type of air
35C 16-18 hrs ambient air
105
lower temp of incubation results to
larger zones of inhibition
106
plates should not be stacked more than
5 high
107
at what temp MRSA not detected
> 35C
108
type of incubation/ ph level wherein activity of some antibiotic is altered
CO2 incubation
109
swarming motility
Proteus vulgaris or Proteus mirabilis
110
appears greenish due to thiocyanine
Pseudomonas aeruginosa
111
effect of prolonged incubation to zone of inhibition
smaller diameter
112