Brainscape's Knowledge GenomeTM

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


See full index

Pharmacology > Antimicrobials > Flashcards

Antimicrobials Flashcards

1
Q

Empiric antimicrobial therapy

A

Use of antimicrobial agents before the pathogen responsible for an illness has been identified, used in cases where there is a significant risk of morbidity if a therapy is withheld until specific pathogen is detected

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

Steps in empiric therapy

A

Formulate clinical diagnosis of microbial infection, obtain specimens for lab, formulate microbiologic diagnosis, determine necessity for empiric therapy, institute treatment

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

Selective toxicity

A

The ability of a drug to injure a target cell or organism without injuring other cells or organisms that should not be injured

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

Methods of selective toxicity

A

Unique target must be present in pathogen but absent in the host OR target must be structurally different in the pathogen than in the host OR target must be more important in the pathogen than in the host

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

Things to consider in the selection of antibiotics

A

Identity and sensitivity of the organism, site of infection, safety of the agent, patient factors, the cost of therapy

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

Narrow spectrum antibiotics

A

Gram positive cocci and gram negative bacilli, gram negative aerobes, Mycobacterium tuberculosis

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

Gram positive cocci and gram negative bacilli

A

Narrow spectrum- penicillin G and V, penicillinase-resistant penicillins (nafcillin methicillin), vancomycin, erythromycin, clindamycin

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

Gram negative aerobes

A

Narrow spectrum- aminoglycosides (gentamicin), cephalosporins (2nd generation)

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

Mycobacterium tuberculosis

A

Isoniazid, rifampin, ethambutol, pyrazinamide

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

Broad spectrum antibiotics

A

Gram positive and negative organisms

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

Gram positive and negative organisms

A

Broad spectrum- broad spectrum penicillins (ampicillin), extended-spectrum penicillins (carbenicillin), cephalosporins (3rd generation), tetracyclines, imipenem, trimethoprim, sulfonamides (sulfamethoxazole), fluoroquinolones (ciprofloxacin, norfloacin)

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

Disruption of bacterial cell wall

A

Without cell walls, bacteria absorb water, swell, and burst, several families of drugs act to weaken cell wall and promote lysis of the bacteria, mammalian cells have no cell wall

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

Disruption of bacterial protein synthesis

A

Synthesis of proteins employs ribosomes, target bacterial ribosomes

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

Inhibition of enzymes unique to bacteria

A

Sulfonamides inhibit bacterial enzyme required for folic acid synthesis, bacteria cannot take up folic acid from environment, mammals do not synthesize folic acid, making it selective

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

Inhibition of nucleic acid

A

DNA gyrase

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

Inhibition of membrane function

A

Fungal membranes

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

Minimal inhibitory concentration (MIC)

A

Minimal concentration where the antimicrobial can inhibit bacterial growth

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

Minimal bactericidal concentration (MBC)

A

Minimal concentration where the antimicrobial kills bacteria

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

Things that determine an anti-microbial’s effectiveness against an organism

A

Antibiotic must bind to its target site in the bacterium, drug most occupy an adequate number of binding sites related to its concentration within the microorganism, antibiotic should remain at the binding site for a sufficient period of time to cause sufficient inhibition

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

Factors that may cause resistance to antibiotics

A

Failure of drug to reach its target, drug inactivation, target alteration

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

Failure of drug to reach its target

A

Outer membrane of a gram negative bacteria is a barrier that excludes large polar molecules from entering the cell, small polar molecules enter through porins

22
Q

Mutations of porin

A

Can cause loss or blockage of a porin that the antibiotic used to gain access to the cell

23
Q

Mutations inhibiting transport mechanisms

A

Can confer resistance to a drug with an intracellular target that requires active transport across the cell membrane (gentamicin)

24
Q

Drug inactivation

A

Bacterial resistance may result from the production of enzymes that modify or destroy the antibiotic

25
Q

Antibiotics affected by drug inactivation

A

Bacteria may develop resistance to aminoglycosides and beta-lactam antibiotics, isoniazid requires bacteria to convert prodrug to active form

26
Q

Target alteration

A

Change in the conformation or binding sequence of the target, antibiotic can no longer bind to the target

27
Q

Efflux pumps

A

Can transport drugs out of cells- tetracyclines, chloramphenicol, fluoroquinolones, macrolides, beta-lactam antibiotics

28
Q

Which antibiotics are most likely to promote resistance

A

Broad-spectrum antibiotics kill off more competing organisms, are more likely to produce resistance

29
Q

Superinfection

A

New infection that appears during the course of treatment of a primary infection, can develop due to elimination of normal flora, most common with broad-spectrum antibiotics

30
Q

Factors of therapeutic objectives

A

Identity of the infecting organism, drug sensitivity of the infecting organism, host factors, drug of choice has greater efficacy, lower toxicity, and is narrow spectrum

31
Q

Alternative agents

A

Should only be used when the first choice drug is inappropriate due to: allergy, inability of drug to penetrate to the site of infection, or unusual susceptibility of the patient to the toxicity of the first choice drug

32
Q

Reasons for therapy with antibiotic combinations

A

Initial therapy of a severe infection, mixed infections, prevention of resistance, decreased toxicity, enhanced antibacterial action

33
Q

Mixed infections

A

Caused by more than one microbe, common in brain abscesses, pelvic infections, infections from perforation of abdominal organs

34
Q

Prevention of resistance

A

Often multiple antibiotic use is associated with promotion of resistance, combinations of drugs are used in tuberculosis

35
Q

Decreased toxicity

A

Combination of flucytosine with amphotericin B in the treatment of fungal meningitis, can reduce dose of amphotericin B and decrease the risk of damage to the kidney

36
Q

Enhanced antibacterial action

A

Penicillins and aminoglycosides in the treatment of enterococcal endocarditis, penicillin weakens cell wall, aminoglycoside suppresses protein synthesis

37
Q

Two antibiotics used together may have different effects

A

Additive, potentiative (synergistic), or antagonistic

38
Q

Additive response

A

Antimicrobial effect of the combination is equal to the sum of the effects of each drug alone

39
Q

Synergistic (potentiative) interaction

A

Effect of the combination is greater than the sum of the effects of the individual agents, one of the two drugs must show a 4-fold increase in activity

40
Q

Synergistic blockade of sequential steps in a metabolic sequence

A

Trimethoprim-sulfamethoxazole for folic acid production

41
Q

Synergistic inhibition of enzymatic inactivation

A

Beta-lactams and beta-lactamase inhibitor (sulbactam)

42
Q

Synergistic enhancement of antibiotic uptake

A

Penicillins increase uptake of aminoglycosides in staph and enterococci

43
Q

Antagonism

A

Combination of two antibiotics may be less effective than one of the agents by itself, usually static agents are antagonistic to cidal agents

44
Q

Examples of antagonism

A

Chloramphenicol and penicillin in treatment of pneumococcal meningitis, tetracycline and penicillin

45
Q

Initial therapy of severe infection

A

Most common indication for use of combination is initial therapy for sever infections of unknown etiology, drug selection can be adjusted once the identity of the microbe is known

46
Q

Penicillins

A

Amoxicillin, bind to PBP, end in “cillin”

47
Q

Tetracyclines

A

Tetracycline, act at 30S ribosome, end in “cycline”

48
Q

Aminoglycosides

A

Streptomycin, affects protein synthesis, “mycin” or “micin”

49
Q

Quinolones

A

Levofloxacin, DNA gyrase inhibitors, end in “oxacin”

50
Q

Cephalosporins

A

Cefaclor, affects protein synthesis, start with “cef” or “ceph”

51
Q

Macrolides

A

Erythromycin, acts at 50S ribosome, end in “mycin”

Pharmacology (15 decks)

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