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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

reason for the smaller diameter of ZoI after prolonged incubation

presence of contaminants

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