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Microbiology > Lecture 18 antimicrobial agents > Flashcards

Lecture 18 antimicrobial agents Flashcards

1
Q

Paul ehrlich

A

german physician and bacteriologist

observed dyes stain in bacterial cells

searched for magic bullet that would kill pathogens without harming human

Salvarsan

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2
Q

Gerhard domagk

A

Red dye prontosil
used to treat step infections in animal

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3
Q

Chemotherapeutic agents

A

Salvrsan, red dye prontosil

chemicals used to treat disease

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4
Q

Who discovered penicillin

A

Fleming

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5
Q

First antibiotic

A

Penicillin G

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6
Q

Selman waksman purified

A

Streptomycin

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7
Q

Selective toxicity

A

Causes greater harm to microbes than human host

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8
Q

Toxicity is relative and expressed as

A

therapeutic index

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9
Q

Therepeutic index

A

lowest dose toxic to patient divided by dose used for therapy

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10
Q

Penicillin G has a ______ therapeutic index

A

high

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11
Q

TI equation

A

LD50/ED50

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12
Q

Bacteriostatic

A

chemicals inhibit bacterial growth

Patient’s defense must eliminate pathogen

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13
Q

Bactericidal

A

chemical kills bacteria

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14
Q

broad-spectrum antimicrobials are important for treating ______ dsiease

A

acute, life-threatening

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15
Q

Negative side effect of broad-spectrum antibmicrobials

A

can disrupt microbiome that helps keep out pathogens, dysbiosis

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16
Q

Narrow spectrum antibiotics

A

affectlimiated range

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17
Q

Narrow spectrum antibiotics requires

A

identification, susceptibility of pathogen

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18
Q

Half life of medication

A

time it takes for serum concentration to decrease by 50%

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19
Q

Half life medication dictates

A

frequency of doses required

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20
Q

adverse effects of antibiotics

A

allergic reactions, toxic effects, dysbiosis

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21
Q

intrinsic resistance

A

structural resistance of bacteria, outer membrane of gram negatives block any meds

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22
Q

Bacterial may develop ______ resistance

A

Acquired

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23
Q

Bacterial processes affected by antibiotics

A

cell wall synthesis
protein synthesis
nucleic acid synthesis
metabolic pathways
cell membranes

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24
Q

Beta lactam antibiotics have a ______ and ______ therapeutic infex

A

Beta lactam ring, high

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25
Q

Beta lactam antibiotics competitively inhibit ______

A

Penicillin binding proteins (PBPs)

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26
Q

PBPs

A

catalyze formation of peptide bridges between adjacent glycan strands, disrupt cell wall sythesis

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27
Q

PBPs are only effective against

A

actively growing cells

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28
Q

what does Beta lactam antibiotics do to gram cells

A

peptidoglycan of gram positives exposed
outer membrane of gram negatives blocked

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29
Q

Penicillinase

A

inactivates members of penicillin family

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30
Q

______ inactive a wide variety of beta lactam meds

A

extended spectrum beta lactamase (ESBLs)

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31
Q

gram ______ produce more Beta lactamase than gram ______

A

Negatives, positives

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32
Q

Extended spectrum penicillins have greater activity against ______ species

A

enterobacteriaceae, Pseudomonas

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33
Q

ESBLs have reduced activity against gram______

A

positives

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34
Q

Augmentin

A

Penicillin + beta lactamase inhibtor added to protect penicillin from being degraded by B-lactamase

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35
Q

Cephalosporins

A

resistant to B-lactamase
has low affinity for PBPs of gram positives

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36
Q

Glycopeptide antibiotics

A

bind to amino acid side chain of NAM molecules
Blocks peptidoglycan synthesis

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37
Q

Glycopeptide antibiotics are only effective against gram ______

A

positives

38
Q

Side effects of glycopeptide antibiotics give ______ TI

A

Low

39
Q

most widely used glycopeptide

A

Vancomysin

40
Q

Bacitracin

A

Toxicity limits to topic applications

41
Q

Ribosomes of prokaryotes

A

70S

42
Q

Ribosomes of eukaryotes

A

80S

43
Q

Ribosomes of mitochondria

A

70S

44
Q

Aminoglycosides ______ bind to 30S, causing malfunction

Bacteriocidal

A

Irreversibly

45
Q

Aminoglycosides block initiation of ______,
causes misreading of ______

A

translation
mRNA

46
Q

Aminoglycosides is ineffective against

A

Anaerobes, enterococci, streptococci

47
Q

inhaled form of ______ treats pseudomonas lung infections in cystic fibrosis

A

Tobramycin

48
Q

Tetracyclines ______ bind to 30S

A

Reversibly

49
Q

Tetracyclines block ______ attachment, prevent translation

A

tRNA

50
Q

Tetracyclines are effective against

A

Gram positives, gram negatives

51
Q

Glycylcyclines are effective against bacteria resistant to ______

A

Tetracyclines

52
Q

Macrolides ______ bind to ______ unit

A

reversibly, 50S

53
Q

When is macrolides used

A

When patient is alelrgic to penicillin

54
Q

Macrolides is a bacteriostatic against gram ______

A

positives

55
Q

Macrolides are not effective against

A

Enterebacteriacaea

56
Q

Resistance of macrolides occurs from modification of ______

A

Ribosomal RNA target

57
Q

Chloramphenical binds to ______ subunit

A

50S

58
Q

Chloramphenicol is used to ______ side effect

A

lethal

59
Q

Fluoroquinolones inhibits ______

A

Topoisomerases

60
Q

What is topoisomerases

A

Enzymes that maintain supercoiling of DNA

61
Q

Fluoroquinolines is when ______ breaks, rejoins strands to relieve strain from localized unwinding of DNA

A

DNA Gyrase

62
Q

Rifamycins block ______, prevents initiation of ______

A

RNA polymerase, transcription

63
Q

Rifampin is a bactericidal against gram ______

A

positives

64
Q

Folate inhibitors are most useful for

A

interfering with metabolic

65
Q

Animals lack enzymes to synthesize folate, requires in ______

A

diet

66
Q

Sulfonamides are ______ drugs

A

Sulfa

67
Q

Sulfa drugs are similar to ______, so enzymes binds chemical

A

PABA

68
Q

______ inhibits enzyme in later step

A

Trimethoprim

69
Q

Sulfa drugs is an example of ______

A

competitive inhibition

70
Q

Combination of trimathoprim and sulfonamide forms

A

Co-trimoxazole

71
Q

Daptomycin inserts into ______

A

cytoplasmic membrane

72
Q

Daptomycin is ineffective against ______

A

gram negatives

73
Q

Polymyxins bind to membranes of ______

A

gram negatives

74
Q

______ drugs are effective to mycobacterium

A

First line

75
Q

______ inhibits mycolic acid synthesis

A

Isoniazid

76
Q

______ inhibits enzymes required for other cell component synthesis

A

Ehtambutol

77
Q

______ interferes with protein synthesis

A

Pyrazinamide

78
Q

kirby bauer disc diffusion test

A

sample of strain uniformly spread on agar with different antibiotics placed

drugs diffuse outwards

zone of inhibition used to determine whether strain is susceptible

79
Q

minimum inhibitory concetrion

A

lowest concentration that prevents growth in vitro

80
Q

Minimum bacterial concentration

A

lowest concentration that kills all cells in vitro

81
Q

Resistance to antimicrobial meds is increasing because

A

increasing use, misuse for resistant microorganisms

82
Q

Antibiotic inactivation enzymes

A

bacteria produce enzymes that interfere with drug

83
Q

example of antibiotic inactivation enzymes

A

Penicillinase, extended spectrum B-lactamase

84
Q

Alteration in target molecule

A

Minor structural changes to target can prevent binding

85
Q

Decreased uptake of medication

A

caused by changes in porin proteins which selectively permit molecules to pass membrane

stops entry of antibiotic

86
Q

Decreased uptake of medications occurs in gram ______

A

negatives

87
Q

Increased elimination of medication

A

Cell makes more efflux pumps, compound is ejected faster

88
Q

Spontaneous mutations can be caused by a single ______ change in gene

A

base-pair, encodes a ribosomal protein

89
Q

Combination therapy

A

combining multiple medications to a cell with a spontaneous mutation so that at least one of them will kill it

90
Q

gene transfer is commonly ______

A

conjugative transfer of R plasmids which carry several different resistance genes

91
Q

Resistance genes on R plasmids originate from

A

spontaneous mutations
microbes that naturally produce the antibiotic

Microbiology (16 decks)

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