works on narrow range of organisms >>gram+ only or gram- only

Exam 4 Chapter 14 Flashcards by Craig Henry

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spectrums of activity

Narrow and broad

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narrow spectrum def

works on narrow range of organisms&raquo_space;gram+ only or gram- only

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broad spectrum def.

work on broad range of organisms

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half-life def.

time it takes for the body to eliminate one half the original dose in a serum

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half-life func.

dictates frequency of dosage

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synergestic def.

action of one drug enhances another

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antagonstic effect def

action of one drug inteferes with another

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additive effect def.

drug combo is neither synergestic or antagonistic

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adverse effects of antimicrobial drugs

allergies
toxic
suppression of normal flora
antimicrobial resistance

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5 targets of antibiotics

Cell Wall/Protein/Nucleic Acid Synthesis
cell membrane integrity
metabolic pathways

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GROUPS OF DRUGS THAT TARGET CATEGORIES*
figure on slide 11

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bacterial cells contain ____________ in their cell wall versus animal cells that do not

peptidoglycan

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B-lactam drugs func.

intefere with peptide chain formation

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bacitracin func.

inhibit cell wall synthesis

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aminoglycosides func.

block initiation of translation

30s ribosome

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macrolides func.

prevent protein synthesis continuation

50s ribosome

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tetracyclines func.

block attachment of tRNA to ribosome 30s

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chlorampenicol func.

prevents peptide bonding

50s ribosome

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lincosamides func.

prevent protein synthesis continuation

50s ribosome

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streptogramins func.

inteferes with peptide bond formation

50s ribosome

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oxazolidinones func.

intefere with initiation of protein synthesis

50s ribosome

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nucleic acid synthesis inhibition targeting

prokaryotic enzymes involved in dna or rna synthesis

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fluoroquinolones func. (disrupts?)

inhibit action of DNA gyrase (disrupts DNA supercoiling)

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Rifamycins func.

block prokaryotic RNA polymerase

folic acid is necessary for ________ ________

nucleotide biosynthesis

antimicrobrial drugs that inhibit metabolic pathways

sulfonamides and trimethoprim

most common antibiotic that inteferes with cell membrane integrity

Polymyxin B

paradox of antimicrobial use

resistance

variety of mechanisms for resisting antimicrobials (4)

drug-inactivating enzymes alteration in the target molecule decreased uptake of drugs increased elimation of the drug

# Resistance to Antimicrobial Drugs drug-inactivating enzymes func.

organisms produce enzymes that chemically modify drug (chloramphenicol acetyltransferase alters chloarmphenicol making it ineffective)

Penicillinase breaks __-_____ _____ of penicillin antibiotics

β-lactam ring

# Resistance to Antimicrobial Drugs alteration of target molecule func.

minor structural changes in antibiotic target can prevent binding ## Footnote Alterations in penicillin-binding proteins prevent β-lactam drugs from binding

Decreased uptake of the drug func.

Alterations in porin proteins in outer membrane of Gram (-) cells decrease permeability of cells | Prevents certain drugs from entering

# Resistance to Antimicrobial Drugs Increased elimination of the drug how?

efflux pumps: transports detrimental compounds out of a cell Increases overall capacity of organism to eliminate drug | Enables organism to resist higher concentrations of drug

# Resistance to Antimicrobial Drugs Acquisition of resistance can be due to ________ ______ | vertical evolution

spontaneous mutation (aka vertical evolution)

spontaneous mutation leads to what?

alteration of existing genes

Acquisition of resistance can be due to ___ ____ | horizontal tranasfer

new genes; acquired by transfer of new genes

T/F spontaneous mutation occurs at an alarming rate

F; relatively low rate

example of spontaneous mutation:

Resistance to streptomycin is result of a change in single base pair encoding protein to which antibiotic binds

when is it is much more difficult for an organism to achieve resistance through spontaneous mutation?

when an antimicrobial has several targets

what is the most common mechanism of gene transfer?

conjugation

conjugation involves the transfer of what?

the R plasmid

T/F plasmids often carry only one resistance gene

F; R plasmid often carries several different resistance genes | Each gene mediating resistance to a specific antibiotic ## Footnote Organism acquires resistance to several different drugs simultaneously

# Antiviral Drugs what do viruses rely on for survival?

host cell's machinery

# Antiviral Drugs viral polymerases def/func

the enzymes that replicate the virus

# Antiviral Drugs antiviral drugs must target what?

viral polymerases

# Antiviral Drugs t/f antiviral drugs are usually broad spectrum

F; only effective against specific types | None eliminate lysogenic virus

# Antiviral Drugs entry inhibitors func.

prevent HIV from entering host cells

# Antiviral Drugs how does Enfuvirtide prevent HIV?

binding to an HIV protein | necessary for membrane fusion

# Antiviral Drugs how does Maraviroc work against HIV

by blocking cell receptors

# Antiviral Drugs viral uncoating drugs (2)

amantadine and rimantadine

# Antiviral Drugs viral uncoating drugs mode of action

blocking a viral protein needed for uncoating of influenza virus after entry | Prevents severity and duration of disease

# Antiviral Drugs T/F viral uncoating develops resistance frequently

T; may limit effectiveness of drug

# Antiviral Drugs nucleotide analog drug examples (3)

Zidovu-dine (AZT) Didanoi-sine (ddl) Lamivu-dine (3TC)

# Antiviral Drugs Nucleotide analog mode of action

termination of growing nucleotide chain

# Antiviral Drugs how do antiviral drugs inhibit activation of viral polymerases (viral replicating enzymes)

allosteric binding

# Antiviral Drugs: Non-nucleotide polymerase inhibitor Non-nucleotide polymerase inhibitor drug examples (2)

Foscarnet and Asyclovir | Used to treat cytomegalovirus and herpes simplex virus

# Antiviral Drugs: Non-nucleotide reverse transcriptase inhibitor how do antiviral drugs inhibit activity of reverse transcriptase

allosteric binding

# Antiviral Drugs Non-nucleotide reverse transcriptase inhibitor drug examples (3)

Nevira-pine, delavir-dine, efavi-renz | Used in combination to treat HIV

# Antiviral Drugs Integrase Inhibitor works how?

inhibiting HIV-encoded enzyme integrase | Prevents virus from inserting the DNA copy of its genome into the genome

# Antiviral Drugs Integrase Inhibitor drug example (1)

Raltegr-avir

# Antiviral Drugs Protease inhibitor works how?

inhibits HIV-encoded enzyme protease | Enzyme essential for production of viral particles

# Antiviral Drugs Protease inhibitor drug examples (2)

Indin-avir and Riton-avir

# Antiviral Drugs Neuraminidase inhibitor works how?

Inhibits neuraminidase enzyme of influenza | Enzyme essential for release of virus

# Antiviral Drugs Neuraminidase inhibitor drug examples (2)

Zana-mivir and Oselta-mivir

# Antifungal Drugs T/F There are many systemic drugs available for fungal pathogens

F; eukaryotes liimit available targets for **selective toxicity (creating vaccine)**

# Antifungal Drugs targets of antifungals:

Synthesis of: **plasma membrane(ergosterol)** cell wall nucleic acid

# Antifungal Drugs: plasma membrane synthesis and function what is the **main target** for antifungal drugs?

ergosterol; steroid in fungal plasma membranes

# Antifungal Drugs Drugs targeting ergosterol include (3)

Polyenes Azoles Allylamines

# Antifungal Drugs How does Polyenes combat fungal infections?

disrupts fungal membrane by binding to ergosterol | Causes leakage of cytoplasmic contents leading to cell death ## Footnote Produced by Streptomyces

# Antifungal Drugs T/F Polyenes is very toxic to humans

T | Limited to use in life-threatening disease

# Antifungal Drugs Polyenes alternative?

Nystatin | used topically

# Antifungal Drugs Azoles are _______ synthesized drugs

chemically | Includes two classes

# Antifungal Drugs two classes of Azoles:

Imidazoles and Triazoles

# Antifungal Drugs Azoles both inhibit what?

Both inhibit synthesis of ergosterol

# Antifungal Drugs Triazoles examples (2)

Fluconazole and Itraconazole | used for systemic infections

# Antifungal Drugs Imidazoles include: (1)

Miconazole | used in topical creams and ointments

# Antifungal Drugs how do allyamines combat fungal infections

Inhibit pathway of ergosterol synthesis | Administered topically

# Antifungal Drugs what are allyamines used to treat?

dermatophyte infections

# Antifungal Drugs Allylamines examples(2)

Nafti-fine and Terbina-fine

# Antifungal Drugs Echinocandins disrupt what?

cell wall synthesis | Used to treat Candida infections ## Footnote Family of agents that interfere with synthesis of glucan component of fungal cell wall

# Antifungal Drugs Griseofulvin disrupts what?

cell division | Appears to interfere with action of tubulin ## Footnote Used to treat skin and nail infections

# Antifungal Drugs Flucytosine disrupts what?

Nucleic acid synthesis | Synthetic derivative of cytosine ## Footnote Inhibits enzymes required for nucleic acid synthesis

Which is the target of the class of antimicrobial drugs known as fluoroquinolones? RNA polymerase helicase DNA gyrase DNA polymerase

DNA gyrase

The penicillins act on which type of bacteria? gram-negative bacteria only mostly gram-negative bacteria and some gram-positive bacteria gram-positive bacteria only mostly gram-positive bacteria and some gram-negative bacteria

mostly gram-positive bacteria and some gram-negative bacteria

How does penicillin work? Penicillin binds to penicillin-binding proteins, thus inhibiting the transpeptidation reaction during cell wall synthesis. Penicillin blocks the movement of peptidoglycan subunits from the cytoplasm to the exterior of the cell. Penicillin binds to penicillin-binding proteins, thus inhibiting the transglycosylation reaction during cell wall synthesis. Penicillin inserts into the plasma membrane, causing cell lysis.

Penicillin binds to penicillin-binding proteins, thus inhibiting the transpeptidation reaction during cell wall synthesis.

Reverse transcriptase inhibitors, such as AZT, can be used to target which virus? rabies HIV herpes influenza

HIV

The macrolides target which feature of the bacterial cell? 30S ribosomal subunit cell wall plasma membrane 50S ribosomal subunit

50S ribosomal subunit

Most antifungal agents target ________, which is found in the fungal cell membrane. cholesterol chitin ergosterol peptidoglycan

ergosterol

Which is the target of the antimicrobial drug known as rifampin? RNA polymerase DNA polymerase DNA gyrase helicase

RNA polymerase

The aminoglycosides directly target which structure of the bacterial cell? cell wall 30S ribosomal subunit 50S ribosomal subunit plasma membrane

30S ribosomal subunit

Sulfa drugs (sulfonamides) inhibit which metabolic pathway? pentose-phosphate pathway Entner–Doudoroff pathway Embden-Meyerhof pathway folic acid synthesis pathway

folic acid synthesis pathway

Exam 4 Chapter 14 Flashcards

(94 cards)