Anti-infective Agents Flashcards Preview

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Flashcards in Anti-infective Agents Deck (26):
1

Germicidal agent

Kills the microorganism

2

Germistatic agent

Prevents the microorganism's growth

3

Disinfectant

Destroys "bugs" on inanimate objects

4

Antibacterial properties of alcohols

Primary alcohols: antibacterial properties increase with molecular weight (through octanol)
Branching decreases antibacterial properties

5

Phenols

One of the first classes of compounds to be used as a surgical antiseptic
Today, fairly obsolete (skin irritants)
Alkyl, aryl, and halogen substitution increase potency

6

Oxidizing agents

Exert activity through generation of oxygen or oxygen radicals in tissues
Especially effective against anaerobic bacteria
Topical treatments (ex-benzoyl peroxide)

7

Iodine

Inhibits proteins: iodinates aromatic amino acid residues and oxidizes sulfhydryl groups (cysteine)

8

Hypochlorous acid (HClO)

Usually exist as hypochlorite salts
Chlorinates nitrogen atoms in amides and oxidizes sulfhydryl groups in proteins

9

Cationic surfactants

Detergents, which can be used as anti-infectives
Common structural features: quaternary nitrogen atom and long aliphatic tail

10

Preservatives

Compounds added to foods, drugs, and cosmetics that prevent microbial contamination
Typically effective at low concentrations and non-toxic to host

11

2 types of fungal infections

Superficial (ringworm, skin, and nail infections)
Deep-seated (systemic infections)

12

Source of selectivity for targeting fungal infections

Fungi use ergosterol in their lipid bilayers, whereas humans use cholesterol

13

Topical antifungal agents

Fatty acids (resemble natural antifungal on skin)
Phenols and derivatives: interfere with cell membrane integrity and function in fungi

14

Antimetabolites

Drugs that prevent the production or degradation of a normal cellular metabolite

15

Flucytosine

Nucleoside antifungal that is used to treat systemic infections
Converted into 5-fluorouracil in the body, preventing synthesis of thymine (and thus, DNA)

16

2 classes of antifungal antibiotics

Polyenes
Griseofulvin
Natural products: hard to synthesize

17

Allylamine antifungals

Act by interfering with ergosterol biosynthesis: inhibit squalene epoxidase while leaving mammalian enzymes unaffected

18

Azole antifungals

Broadly effective against many topical and systemic infections
At low concentrations, inhibit fungal cell growth (inhibit membrane-bound enzymes)
At high concentrations, kill fungal cells (cause damage to cell membranes)

19

Quinolones

Synthetic antibacterial agents derived from nalidixic acid
Inhibit bacterial DNA synthesis via inhibition of DNA gyrase

20

Quinolone SAR

Must have alkyl group bound to nitrogen
Adding substituents to carbon atom to the right of the nitrogen removes activity
Adding a fluorine at C6 (4 carbons to the left of the nitrogen) increases activity

21

First developed effective systemic agents for bacterial infections

Sulfonamides (sulfa drugs; original drug: prontosil)

22

How sulfonamides work

Inhibition of tetrahydrofolate (THF) coenzyme synthesis from pteridine diphosphate and p-aminobenzoic acid (PABA)

23

Limitations of sulfonamides

Can cause crystalluria (crystallizing in kidney, damaging it)
Have been overprescribed: some bacterial strains are resistant to it (can increase synthesis of PABA, competing with the drug, or can pump the drug out faster than it can enter)

24

Sulfonamide SAR

Aniline ring is necessary for activity (cannot be alkylated)
Sulfonamide portion of molecule (SO2 and amine) is most likely the active structure

25

Trimethoprim

Antibacterial agent: inhibits dihydrofolate reductase (enzyme required for synthesis of tetrahydrofolate coenzyme)

26

Sulfones

Less effective than sulfonamides, but effective in treating leprosy
Dapsone is the only one with appreciable clinical utility