Antibiotics 1 Flashcards

1
Q

Describe the nomenclature of bacteria

A

Named by common characteristics. Also named by genus and species.

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2
Q

what is the cell wall made of

A

Peptidoglycan

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3
Q

What is peptidoglycan

A

a macromolecule composed of peptides and sugars that provide a rigid support structure found only in bacteria. Thick wall of peptidoglycan is gram +

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4
Q

What is lipopolysaccharide

A

makes outer membrane strctr of gram - bacteria cell wall and consists of phospholipid and polysaccharides.

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5
Q

What is cytoplasmic membrane

A

similar in strctr to eukaryotic cell membrane(except sterols)

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6
Q

What is LPS’s effect on antibiotics

A

retards or prevents penetration of bulky, high molecular weight antibiotics like erythromycin

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7
Q

Lipid bilayer of cytoplasmic membrane

A

penetration of water soluble drugs is severely hindered

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8
Q

Hydrophillic pores

A

allow penetration of water soluble molecules up to 650 Daltons, such as sulfonamides.

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9
Q

Nutrient receptor prtns on outer membrane

A

Agents structurally related to nutrients (sideromycins) utilize these natural receptors

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10
Q

Teichoic and Teichuronic acid

A

strong anionic character of these polymers may affect rate of penetration

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11
Q

What is selective toxicity

A

kill or impair growth of specific target organisms w/o harming host

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12
Q

What is a narrow spectrum antibiotic

A

drug that has effect on one type of species or organism. Use if organism known

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13
Q

Broad spectrum?

A

drug has effect on a wide variety of organisms. Use if causative agent unknown. Tetracycline can be used to treat both gram negative and gram positive.

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14
Q

Difference bw prophylactic and pre emptive therapy?

A

Prophylactic is treatment in absence of infection in order to prevent disease. Pre emprive is treatment of high risk pts that have become infected but are asymptomatic

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15
Q

Empirical therapy

A

treatment of symptomatic pt w/o further testing or confirmation of organism

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16
Q

Definitive therapy

A

treatment once pathogenic org has been identified and appropriate drug identified

17
Q

Suppressive therapy

A

generally a low dose therapy used as a secondary prophylaxis. Problem that caused initial infection is likely still present.

18
Q

What are the “ESKAPE” organisms

A

commonly drug resistance bugs-Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumanni, Pseudomonas aeruginosa, Enterobacter species

19
Q

Resistance in daptomycin

A

Gene mutation changes charge of membrane, making net postive at outer and inner membrane. Repels Ab with positive charge

20
Q

Tetracycline

A

Orgs express efflux pump

21
Q

Metronidazole

A

Must be reduced to activate drug. Mutation in rdxA gene alters or decreases activation of the drug.

22
Q

Aminoglycosides such as streptomycin

A

Aminoglycoside modifying enzymes chemically modify the antibiotic and alter the binding of the drug to its target.

23
Q

Amoxicillin

A

B lactamase can hydrolyze the lactam ring of amoxicillin (as well as other penicillins and cephalosporins) and render the compound ineffective

24
Q

Trimethoprim and sulfonamides

A

Expression of drug insensitive enzymes dihydropteroate synthase and dihydrofolate reductase

25
Q

Vancoymycin

A

Substitution on the peptidoglycan stem so that agent can no longer bind to target