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Microbiology > Mechanisms of Action of Abs > Flashcards

Mechanisms of Action of Abs Flashcards

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Biology 101 flashcards
1
Q

What is Pharmacokinetics?

A

Encompasses all the ways that the body manipulates a drug

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2
Q

What are the ways the body manipulates the drug?

A

Absorption
Distribution
Metabolism
Excretion

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3
Q

What is Pharmocodynamics?

A

Describes biochemical and physiological effects of the drug and its mechanism of action on the bacteria

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4
Q

What is a Bacteriostatic?

A

Antimicrobial agents that INHIBIT the growth/reproduction of the infecting agent
BUT do not actually kill it

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5
Q

What are some examples of Bacteriostatics? (6)

A 
Ma-cro-lids --> (E-ry-thro-my-cin)
Clin-da-my-cin
Sulfa-me-thox-a-zole
Tri-me-thro-pin
Te-tra-cy-clins
Chlo-ram-phe-ni-col
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6
Q

What is a Bacteriocidal?

A

Antimicrobial agent that is capable of causing IRREVERSIBLE damage/death to the organism

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7
Q

What are some ex of Bacteriocidals? (5)

A

Beta-lactam Abt –> (Penicillins and Ce-pha-la-sporins)
Va-co-my-cin
Amino-gly-co-sides –> (Gen-ta-my-cin)
Fluo-ro-qui-no-lones (Ci-pro-flox-a-cin)

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8
Q

What factor affects wether a drug exhibits bacterio -static or -cidal?

A

It is the antimicrobial concentration at the site of action

ATM may be -static at low [C], but -cidal at high [C]

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9
Q

What is Minimal Inhibitory Concentration?

A

Minimal amount of antimicrobial that will inhibit the visible growth of a microorganism after overnight incubation

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10
Q

What are broad spectrum Ab?

A

One that is active against a wide range of bacteria (gram +/-)
Used priorly to ID’ing the causative bacteria

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11
Q

What are narrow spectrum Ab?

A

ACtive against a select group of baterial types

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12
Q

What are the FIVE mechanisms of action, that Abs use to inhibit or kill bacteria?

A

Interference with cell wall synthesis (MOST COMMON)
Interference with protein synthesis
Interference with cytoplasmic mem function
Interference with nucleic acid synthesis
Interference with metabolic PW

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13
Q

What do most agents in the “inhibitors of cell wall synthesis” interfere with?

A

Peptidoglycan synthesis and murein assembly

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14
Q

What agents are included in “inhibitors of cell wall synthesis”?

A

Beta-lactam Abs

Glycopeptides

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15
Q

What are the Beta-lactam ABs? (5)

A

Penicillins
Cephalosporins
Monobactams
Carbapenems

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16
Q

What is the mechanism of action of Beta-lactam Abs?

A

Bind at active site of the transpeptidase En that cross-links the peptidoglycan strands - IRREVERSIBLY inhibits En
–>Formation of cell wall is prevented

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17
Q

What are the four generations in cephalosporin?

A

Each generation exhibits increased spectrum of activity as well as increased RESISTANCE to destruction by
Beta-lactamase En’s

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18
Q

What are Monobactams active against?

A

Aerobin gram (-) BACILLI

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19
Q

What are Carbapenems active against?

A

All pathogenic organisms ans resistant to destruction by the extended spectrum B-lactamses (ESBL’s)

20
Q

What are glycopeptides (vancomycin)?

A

They are another type of antimicrobials that interfere with cell wall synthesis

21
Q

How are glycopeptides inhibitors of cell wall synthesis?

A

They act by BINDING to the D-alanyl-D-alanine residues – preventing the cross linking of the peptidoglycan sheets

EFFECTIVE ONLY AGAINST GRAM (+)

22
Q

How is Fosfomycin an inhibitor of “cell wall” synthesis?

A

Inhibits phos-pho-enel pyruvate –> halting MURAMIC ACID synthesis (outside of acid-fast bacteria)

23
Q

What are the 3 main mechanisms in which “agents of the inhibitors of protein synthesis” inhibit protein synthesis?

A

1- Interfere with the formation of the 30S initiation complex (mRNA, 30S, tRNA)
2- Interfere with the formation of the 70S ribosome (30S initiation complex and 50S ribosome)
3- Block elongation process of assembling A.A’s into polypeptides

24
Q

What are the main agents in this group? (6)

A 
Aminoglycosides
Linezoid
Macrolids
Lincosamides
Chloramphenicol
Tetracyclines
25
Q

What do aminoglycosides do?

A

Bind to the 30S ribosome and change its shape
–>inhibits protein synthesis by causing a misreading of mRNA
BACTERIOCIDAL

26
Q

What do Linezoids do?

A

Block translation of the initiation complex by binding to the 23S portion of the 50S subunit
BACTERIOSTATIC

27
Q

What do Macrolids do?

A

Bind to 23S rRNA molecule (in 50S subunit)
–>Block exit of growing polypeptide chain
BACTERIOSTATIC

28
Q

What do Lincosamides do?

A

Bind to 50S
Disrupt protein synthesis by interfering with the transpeptidation reaction
–>inhibits early chain elongation
BACTERIOSTATIC

29
Q

What do Chloramphenicals do?

A

Binds to residues in 23S (on 50S)
Preventing peptide formation
BACTERIOSTATIC

30
Q

What do Tetracyclines do?

A

Block attachment of the tRNA to the 30S ribosome subunit
Inhibitors of the codon-anticodon interaction
Can inhibit protein synthesis in both 70S and 80S
BACTERIOSTATIC

31
Q

What agents interfere with cytoplasmic mem func?

A

Polymyxins
Bacitracin
Anti-fungals

32
Q

How do Polymyxins do it?

A

With cationic detergent-like activity

33
Q

How do Bacitracin do it?

A

Disrupt cytoplasmic membranes

34
Q

How do anti-fungals do it?

A

Alteration of sterol structure and function

35
Q

How is nucleic acid synthesis inhibited by agents? (3)

A

They interfere with DNA
They interfere with RNA
They are nucleoside anologs

36
Q

What are the agents that interfere with DNA? (2)

A

Quinolones/Fluoroquinolones

Metronidazole

37
Q

What do Quinolones/Fluoroquinolones do?

A

inhibit DNA gyrases or topoisomerases (required for supercoiling)
BACTERIOCIDAL

38
Q

What do Metronidazoles do?

A

Cause metabolic cytotoxic byprodcuts
–>disrupt DNA
BACTERIOCIDAL

39
Q

What are the agents the agents that interfere with RNA? (2)

A

Rifampin

Bacitracin

40
Q

How does Rifampin do it?

A

Binds to DNA-dependent RNA polymerase
–>inhibiting initiation of RNA synthesis
BACTERIOCIDAL

41
Q

How does Bacitracin do it?

A

inhibits RNA transcription

BACTERIOCIDAL

42
Q

What are the nucleoside analogs for viruses?

A

Acy-clovir

43
Q

What are the nucleoside analogs for retroviruses?

A

Zido-vu-dine

44
Q

What are the agents that can cause interference in the metabolic PW? (5)

A

Sulfonamides and Dapsone
Trimethropim
Trimethropim and Sulfamethoxazole

45
Q

How does Sulfonamides and Dapsone do it?

A

Sulfonamides is a BACTERIOSTATIC and Dapsone in a BACTERIOCIDAL
Compete with p-aminobenzoic acid (PABA)
–>Prevent synthesis of folic acid

46
Q

How does Trimethropim do it?

A

inhibits dihydrofolate reductase
–>preventing synthesis of folic acid
BACTERIOSTATIC

47
Q

How does Trimethropim and Sulfamethoxazole do it?

A

Drugs used in combination (BACTRIM)
Are synergetic in activity
BACTERIOCIDAL

Microbiology (10 decks)

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