Brainscape's Knowledge GenomeTM

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


See full index

Infectious Disease and Microbiology > Microbial Growth Control > Flashcards

Microbial Growth Control Flashcards

1
Q

_______ are routinely used to control microbial growth

A

chemicals

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

antimicrobial agent

A

natural or synthetic chemical that kills or inhibits the growth of microorganisms

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

Agents that kill organisms are called_____

A

cidal agents

-prefix indicates type of organism killed

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

agents that dont kill but only inhibt growth are called____

A

static

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

antimicrobial agents can differ in their

A

selective toxicity

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

_______ agents are _____ toxic for _____ than for _____ tissues

A

selective, more, microorganisms, animal

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

antimicrobial agents with selective toxicity are especially useful for treating infectious diseases because

A

they kill selected microorganims in vivo without harming the host

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

antibacterial agents can be classified as

A

bacteriostatic, bactericidal and bacteriolytic

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

viable cells are measured by

A

plate counts

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

bacteriostatic agents are frequently

A

inhibitors of protein synthesis

-act by binding to ribosomes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Bacteriocidal agents

A

bind tightly to their cellular targets, arent removed by dilution, and kill cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

some cidal agents are also

A

lytic agents

-kills by cell lysis and release of cytoplasmic contents

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

lysis_____ the_____ _____ _______ and the _____ _____ _____ shown by a ________ in _______ ______

A

lysis decreases the viable cell number and also the total cell number shown by a decrease in culture turbidity

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

bacteriolytic agents include

A

ATB that inhibit cell wall synthesis

-such as Penicillin

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

How many phases is the typical growth curve for population of cells grown in a closed system characterized by?

A

Four

-lag phase, exponential phase, stationary phase, death phase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

lag phase

A

interval between when a culture is inoculated and when growth begins

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

exponential phase

A

cells in this phase are typically in the healthiest state

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

stationary phase

A

either an essential nutrient is used up or waste product of the organism accumulates in the medium

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

death phase

A

if incubation continues after cells reach stationary phase the cells will eventually die

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

What establishes the relationship between viable and total cell counts?

A

The turbidity of each culture coupled with viable plate counts

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

antimicrobial activity

A

measured by determining the smallest amount of an agent needed to inhibit the growth of a microorganism (MIC)

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

Minimum Inhibitory Concentration (MIC)

A

lowest concentration of agent that completely inhibits the growth of the test organism (Tube dilution technique)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

To determine the MIC for a given agent against a given organism

A

a series of culture tubes is prepared and inoculated with the same number of microorganisms
-each tube contains medium with increasing concentration of the agent

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

turbidity

A

visible growth

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

MIC varies with

A

organism used, inoculum size, composition of culture medium, incubation time and condition of incubation (temp, pH and aeration)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

disc diffusion technique

A

common assay for antimicrobial activity

  • petri dish containing an agar medium inoculated with a culture test organism
  • known amount of antimicrobial agent added to filter paper discs
  • agent diffuses from disc into agar establishing gradient
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

The_________ the chemical diffuses away from the filter paper the ______ the concentration of the gradient

A

farther, lower

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

zone of inhibiton

A

created with a diameter proportional to the amount of antimicrobial agent added to the disc, the solubility of the agent the diffusion coefficient and the overall effectiveness of the agent

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What technique is routinely used to test pathogens for ATB susceptibility?

A

disc diffusion technique

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Two categories chemical antimicrobial agents for external use divided into

A
  • Products used to control microorganisms in commercial and industrial applications
  • Products designed to prevent growth of human pathogens in inanimate environments and on external body surfaces
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Sterilants, disinfectants, sanitizers

A

decontaminate nonliving materials

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

antiseptics and germicides

A

to reduce microbial growth on living tissues

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

sterilants

A

destroy all forms of microbial life including endospores

-chemical sterilants (sterilizers or sporocides)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

Sterilants are used in situations where

A

it is impractical to use heat or radiation for decontamination or sterilization

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

Cold sterilization

A

performed in enclosed devices which employ a gaseous chemical agent such as Ethylene Oxide (EO)
-alkylating agent that disrupts DNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

Liquid sterilants are used for

A

instruments that cant withstand high temperatures or gas

-Sodium hypochlorite (bleach)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

disinfectants

A

chemicals that fill microorganisms but not necessarily endospores and are used on inanimate objects

  • disinfectants such as ethanol and cationic detergents used to disinfect
  • alcohol (EtOh or isopropanol 70% in water), NaClO 5-8% (bleach)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

sanitizers

A

agents that reduce but may not eliminate microbial numbers to levels considered safe without adversely affecting quality of product or its safety

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

antiseptics and germicides

A

chemical agents that kill or inhibit growth of microorganisms and are nontoxic enough to be applied to living tissues, components used for hand washing or for treating surface wounds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

antimicrobial efficacy

A

several factors affect the efficacy of chemical antimicrobial
-many disinfectants are neutralized by organic material

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

Only _____ are effective against _______ endospores

A

sterilants, bacterial

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

Mycobacterium tuberculosis is resistant to

A

action of common disinfectant because of the waxy nature of the cell wall

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

antimicrobial drugs are classified based on their

A

molecular structure, mechanism of action, spectrum of antimicrobial activity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

What are the two broad categories antimicrobial agents fall into?

A

Synthetic agents and antibiotics

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

Synthetic antimicrobial drugs

A

growth factor analogs:salvarsan, isoniazid
nucleic acid base analogs: fluorouracil, bromouracil
quinolones: ciprofloxacin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

naturally occuring antimicrobial drugs: antibiotics

A

beta-lactam antibiotics: penicillin and cephalosporins

antibiotics from prokaryotes : amynoglicocides, macrolides, tetracyclins, daptomycins, platensimycin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

Cell wall synthesis

A

cycloserine, vancomycin, bacitracin, penicllins, cephalosporins, monobactams, carbapenems, amoxicillin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

DNA gyrase

A

nalidixic acid, ciprofloxacin, novobiocin

49
Q

RNA elongation

A

Actinomycin

50
Q

DNA directed RNA polymerase

A

Rifampin, streptovaricins

51
Q

Protein synthesis

50S inhibitors

A

Erythromycin (macrolides)
Chloramphenicol
Clindamycin
Lincomycin

52
Q

Folic acid metabolism

A

Trimethoprim

Sulfonamides

53
Q

Cytoplasmic membrane

structure and function

A

Polymyxins

Daptomycin`

54
Q

Protein synthesis

30S inhibitors

A 
Tetracyclines
Spectinomycin
Streptomycin
Gentamicin
Kanamycin
Amikacin
Nitrofurans
55
Q

lipid biosynthesis

A

platensimycin

56
Q

Protein synthesis

tRNA

A

mupirocin, puromycin

57
Q

each antimicrobial agent

A

affects a limited and well-defined group of microorganism

58
Q

Systematic work on Antimicrobial Drugs was first initiated by

A

paul ehrlich
-Nobel prize wining,
German, physician, scientist)
-selective toxicity

59
Q

selective toxicity

A

ability of a chemical agent to inhibit or kill a pathogen microorganisms
without adversely affecting the host

60
Q

salvarsan

A

one of the first antimicrobial drugs, an Arsenic-containing compound
used for the treatment of syphilis (T. pallidum), was the most successful
-adminstered intramuscularly

61
Q

growth factor analogs (GFA)

A

specific chemical substances
required in the medium because the organism can
not synthesize them
-structurally similar to growth factors but do
not function in the cell
-GFA disrupts cell
metabolism
-used in the treatment of viral and fungal
infections and as mutagens

62
Q

sulfa drugs

A

discovered by Gerhard Domagk in the 1930s

-selectively toxic in bacteria because they synthesize their own folic acid

63
Q

Sulfanilamide blocks the synthesis of _____ thereby inhibit __________ synthesis

A

folic acid, nucleic acid

64
Q

isoniazid

A 
Growth Factor Analog
effective only against Mycobacterium
-Interferes with synthesis of Mycolic acid,
a mycobacterial cell wall component
-most effective single
drug used for control and treatment
of TBC
65
Q

Nucleic acid base analogs have been formed by

A

the addition of Bromine or Fluorine atoms

66
Q

fluorine

A 
relatively small atom and
does not alter the overall shape of the
nucleic acid base
-changes the
chemical properties so compound does not function in cell
metabolism
-blocks nucleic acid
synthesis
67
Q

quinolones

A

antibacterial compounds that interfere with bacterial DNA gyrase (Ciprofloxacin), prevents the supercoiling of DNA, a required step for packing DNA in the
bacterial cell.

68
Q

DNA ______ is found in ____ bacteria

A

gyrase, ALL

69
Q

________ are effective for treating

both _______ and ________, bacterial infections.

A

Fluoroquinolones, Gram-positive, Gram-negative

70
Q

Fluoroquinolones such as Ciprofloxacin (Cipro) are used to treat

A

uncomplicated UTI
(Urinary Tract Infections), acute bacterial sinusitis, acute bacterial exacerbation of chronic
bronchitis when no other treatments options are available
-drug of choice for treating anthrax

71
Q

Moxifloxacin has been approved for treatment of

A

resistance strains of TBC, Mycobacterium

tuberculosis

72
Q

_______ are naturally produced _______agents produced by microorganisms

A

Antibiotics, antimicrobial

73
Q

natural ATB can often be modified to enhance

A

efficacy (semisynthetic)

74
Q

Who invented penicillin?

A

Alexander Fleming discovered it

75
Q

b-Lactam antibiotics

A

one of the most important
groups of antibiotics of all time.
– Include Penicillins, Cephalosporins, and Cephamycins,
-share a characteristic structural component,
the b-lactam ring

76
Q

penicillin

A

Discovered by Alexander Fleming, 1928
– Primarily effective against Gram-positive bacteria
against Staphylococcal and Pneumococcal infection
– Some synthetic forms are effective against some Gram-
Negative bacteria (Ampicillin, Carbenicillin),
– The structural differences in the N-acyl group allow
them to be transported inside the Gram-negative outer
membrane, where they inhibit cell wall synthesis.
– b-Lactam ATB are inhibitors of cell wall synthesis
– Penicillin binds to transpeptidase enzymes inhibiting the
transpeptidation process (cross-linking of two glycanlinked
peptide chains).
– Some individuals develop allergies to b-Lactam ATB

77
Q

Cephalosporins

A
  • beta-lactam ATB
  • produced by fungus cephalosporium
  • same mode of action as penicillins
  • clinically semisynthetic ATB with broader spectrum of ATB
  • typically more resistant to beta-lactamases
78
Q

What are cephalosporins commonly used to treat?

A

gonorrhea infections

79
Q

For the treatment of Gonorrhea CDC recommends

A

dual therapy

-single dose of 250 mg intramuscular ceftriaxone and 1g of oral Azithromycin (bacterial protein inhibitor)

80
Q

ATB affecting

A

protein synthesis
-Many ATB inhibit protein synthesis by
interacting with the ribosome and
disrupting translation

81
Q

streptomycin inhibits

A

protein chain initiation

82
Q

Puromycin, Chloramphenicol,
Cycloheximide and Tetracycline
inhibit

A

protein chain elongation

83
Q

some ATB specifically inhibit

A

Transcription by inhibiting RNA synthesis

84
Q

Rifampin inhibit RNA synthesis by

A

binding to the β-subunit of

RNA polymerase, also used for the treatment of Tuberculosis

85
Q

aminoglycosides are

A

ATB that contain amino sugars bonded by glycosidic linkage

  • streptomycin: Kanamycin, Netilmicin, Neomycin, Gentamacin, Amikacin
  • target the 30S subunit of the ribosome: inhibits protein synthesis
  • clinically useful against gram-negative bacteria
86
Q

What was the first effective ATB used for the treatment of Tuberculosis (TB)?

A

Streptomycin

87
Q

Both Kanamycin and Streptomycin are synthesized by

A

Streptomyces species

88
Q

macrolides

A

contain lactone rings bonded to sugars

  • large number of macrolide ATB
  • erythromycin best known
89
Q

erythromycin

A

broad spectrum antibiotic
-targets 50S subunit of bacteria ribosome
-inhibits protein synthe
-used in place of penicillin
-only antibiotic ophthalmic ointment recommended for use in
neonates for prophylaxis of Gonococcal

90
Q

Erythromycin is particularly useful for treatment of

A

Legionellosis

91
Q

tetracyclines

A

produced by several species of Streptomyces, are an important group
of ATB
-inhibits almost all Gram-positive and Gram-negative
Bacteria
-basic structure consist of a Naphthacene ring system
-protein synthesis inhibitor , interferes with bacterial 30S ribosome subunit function

92
Q

tetracyclines and b-lactam ATB comprise

A

two most important

groups of ATB in the medical field

93
Q

daptomycin

A
  • produced by streptomyces
  • cyclic lipopeptide ATB
  • used mainly to treat gram + bacteria
94
Q

platensimycin

A 
first member of a new structural class of ATB
-produced by streptomyces platensis
95
Q

antiviral drugs

A

viruses use their eukaryotic host to reproduce and perform metabolic functions, most
antiviral drugs also target host structures, resulting in host toxicity

96
Q

Nucleoside Reverse Transcriptase Inhibitors (NRTI)

A

antiviral agents

97
Q

protease inhibitors (PI)

A

drugs prevents viral replication by
binding the active site of HIV protease
-prevents virus maturation

98
Q

enfuvirtide

A

fusion inhibitor

  • composed of 36-amino acid synthetic peptide
  • binds to gp41 membrane protein
99
Q

What are the two categories of drugs that successfully limit influenza infection?

A

adamantanes: amantadine and rimantadine, synthetic amines that interfere with an influenza A ion transport protein
neuraminidase inhibitors: block the active site of neuraminidase in
Influenza A and B viruses, inhibiting virus release form infected cells.

100
Q

________ are ______ useful than the ______ inhibitors

because resistance to Adamantanes develops rapidly in strains of influenza virus

A

Adamantes, less, Neuraminidase

101
Q

interferons

A

small proteins in the cytokine family that prevent viral multiplication by
stimulating antiviral proteins in uninfected cells

102
Q

Interferons are produce in 3 molecular forms:

A

IF-α (leukocytes), IF-β (fibroblasts), IF-γ (activated lymphocytes)

103
Q

antifungal drugs

A

Fungi pose special problems in terms of treatment because Fungi and Humans are Eukaryotic organisms

104
Q

membrane functions

A

Polyenes bind to
Ergosterol and disrupt
membrane integrity

105
Q

Cell wall synthesis:

A

Polyoxins inhibit Chitin (a long-chain polymer of a N-acetylglucosamine) synthesis
Echinocandins inhibit Glucan (a polysaccharide of D-glucose monomers) synthesis

106
Q

Ergosterol synthesis:

A

Azoles and Allylamines

inhibit synthesis

107
Q

Nucleic acid synthesis:

A

5-Fluorocytosine is a nucleotide
analog that inhibits nucleic
acid synthesis

108
Q

Microtubule formation:

A

Griseofulvin disrupts
microtubule aggregation
during mitosis

109
Q

Ergosterol

A

sterol found in fungi.

It is not present in plant or animal cells

110
Q

Ergosterol inhibitors

A

target the unique fungal plasma membrane component Ergosterol

111
Q

polyenes

A

a group of ATB produce by Streptomyces

-Bind to ergosterol, disrupting membrane function

112
Q

azoles and alylamines

A

synthetic agents that selectively inhibit Ergosterol biosynthesis and therefore have broad antifungal activity.

113
Q

Echinocandins:

A

for systemic fungal infections in immunocompromised patients.
– Inhibit 1,3 b-D glucan synthase (not present in mammals)
-Used to treat Candida albicans and C. auris infections

114
Q

Antimicrobial drug resistance:

A

acquired ability of a microorganism to resist the effects of a chemotherapeutic
agent to which it is normally susceptible

115
Q

Most drug-resistant bacteria isolated from patients contain

A

drug-resistance genes located on R plasmids

116
Q

Resistance is typically due to

A

Genes on the R-factor plasmid that encode enzymes that modify and
inactivate the drug or genes that encode enzymes the prevent the uptake of the drug or actively
pump it out.

117
Q

r plasmid

A

genes encode enzymes that
modify and inactivate the drug or genes that encode enzymes that prevent
uptake of the drug or actively pump it out

118
Q

saquinavir

A

Binds to active site of HIV protease enzyme

119
Q

Bacteriophage therapy

A

the therapeutic use of bacteriophages to treat pathogenic bacterial
infections

Infectious Disease and Microbiology (9 decks)

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