Micro Antimicrobial Mechanisms of Action Learning Goals

antimicrobials are often administered ___

internally

antimicrobials exhibit ___toxicity

selective

what is selective toxicity

more toxic to an infectious microbe than to the host/host cells

what is an antibiotic

a medicine that inhibits or destroys microorganisms, but does not act on viruses

why are antibacterial drugs the easiest to develop

because bacteria have many structures that human cells do not have so Antibiotics can target these structures without significantly harming human cells

antibiotics come from 3 sources

1. natural produces

2. semisynthetic

3. synthetic

many antibiotics are ___ ___ made by various microbes

natural products

what are semisynthetic antibiotics

chemically altered antibiotics that are more effective, longer lasting, or easier to administer than naturally occurring ones

what are synthetic antibiotics

antimicrobials that are completely synthesized in a lab

most new antibiotics are ___ from previous ones

derived

what cell structure do penicillins inhibit

cell wall

what cell structure do cephalosporins inhibit

cell wall

what cell structure do vancomycin inhibt

cell wall

what cell structure do bacitracin inhibt

cell wall

what cell structure do monobactams inhibit

cell wall

what cell structure do polymyxins inhibit

cell membrane

what do sulfonamides inhibit

metabolic inhibitors

what kind of inhibitors is trimethoprim

metabolic inhibitor

what kind of inhibitor are quinolones

DNA replication inhibitor

what does rifampin inhibit

RNA polymerase

what do pyronins inhibit

RNA polymerase

what category is erythromycin in

macrolides

what category is linezolid in

oxazolidinone

what category is synercid in

streptogramins

what category is gentamicin in

aminoglycosides

what category is doxycycline in

tetracyclines

what does chloramphenicol target

50S ribosome subunit

what does chloramphenicol inhibit

protein synthesis

what do macrocodes inhibit

protein synthesis

what do macrocodes target

50S ribosome subunit

what does clindamycin target

50S ribosome subunit

what does clindamycin inhibit

protein synthesis

what do oxazolidinones inhibit

protein synthesis

what do oxazolidinones target

50S ribosome subunit

what do streptogramins target

50S ribosome subunit

what do streptogramins inhibit

protein synthesis

what do aminoglycosides inhibit

protein synthesis

what do aminoglycosides target

30S ribosome subunit

what do tetracyclines inhibit

protein synthesis

what do tetracyclines target

30S subunit

what does cycloserine specifically

d-alanine to peptide chain

what does bacitracin target specifically

the transport of NAG/NAM from cytoplasm to periplasm

what does penicillin target specifically

peptide crosslinks in NAM units in G+ bacteria

what does vanomyicin target specifically

peptide cross links in NAM units in G+ bacteria

what does cephalosporin target specifically

peptide cross links in NAM units in G+ bacteria

what does isoniazid target specifically

disrupts mycologic acid formation

what does ethambutol target specifically

disrupts mycologic acid formation

what does gramicidin target specifically

forms a cation channel that disrupts membrane by creating dimers

how does amphotericin B work

attaches to ergosterol in fungal membranes

what does polymyxin target specifically

disrupts cytoplasmic membranes of G- bacteria

what is polymyxin produced by

bacillus polymyxa

what does polymyxin bind to

LPS

polymyxin is toxic to

human kidneys, so is only used externally

example of metronidazole

flagyl

what does metronidazole target

nucleic acid synthesis

metronidazole needs activation through

by the terminal e- acceptor

is metronidazole aerobic or anaerobic

anaerobic

what do quinolones target

Nucleic acid synthesis

what do quinolones target specifically

act against prokaryotic DNA gyrase

what do fluoroquinlones target specifically

act against prokaryotic DNA gyrase

what do fluoroquinlones target

nucleic acid synthesis

what do reverse transcriptase inhibitors act against

an enzyme HIV uses in its replication cycle

nucleotides interfere with what

the function of nucleic acids

what are nucleotides most often used against and why

viruses because their NA synthesis is more rapid than that of the host cells

oxazolidinones prevent what

70S subunit formation

macrocodes prevent what

peptidyltransferase activity and translocation

ahminoglycosides inhibit what and causes what

translocation and causes misreading of mRNA

tetracyclines prevent what

aminoacyl-tRNA entry into the A site

mitochondria contain ___ ribosomes so inhibition of the bacterial ribosome can be ___ to humans

70S; harmful

phases of translation

1. small ribosome subunit binds to mrna on aug start codon
2. trna delivers f-methionine
3. large ribosomal subunit recretuited to mrna

ahminoglycosides cause change in

30S shape and mRNA is misread

tetracycline blocks

docking site of tRNA

chloramphenicol binds to

tRNA

macrolides bind to ___ and cause __

50S; mRNA to not move, so synthesis stops

RNA interference is aka

RNAi

what happens with RNAi

antisense rna binds to mrna, prevents ribosomal subunit from binding

linezolid other name

Zyvox

what is linezoid used for

drug-resistant G+ infections and mitochondrial toxicity

anti-metabolic agents can be effective when pathogen and host metabolic processes ___

differ

what kind of drugs are sulfa drugs

anti-metabolic

sulfa drugs work because ___ looks like ___

PABA; SFA

humans get folic acid through ___ while bacteria ___ their own

diet; synthesize

folic acid is needed for ___ and ___ ___

DNA/RNA synthesis

what category is amantadine in

anti-metabolic

amantadine prevents

viral uncoating

what category is rimantadie in

anti-metabolic

rimantadine prevents

viral uncoating

weak organic bases are in what category

anti-metabolic

weak bases prevent what

viral uncoating

protease inhibitors are in what category

anti-metabolic

protease inhibitors are the ___ that ___ needs for its replication cycle

enzyme; HIV

streptomyces sp naturally produce what

antibiotics in soil

is penicilin b natural, semisynthetic, or synthetic

natural

cepthalophin is natural, semisynthetic, or synthetic

semisynthetic