Exam #3 Study Guide

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What do Penicillin’s sometimes work against?

cell wall blocker; effective against g+ cocci and treponema pallidum

What is the mechanism of action of amoxicillin, and what is it effective against?

mechanism of action

What does MoA stand for?

antifungal

What is amphotericin B?

binds ergosterol of fungal plasma membrane; binding causes leakage of monovalent cations (K+, NA+, H+)

What is the mechanism of action of amphotericin B?

cell wall blocker; effective against G+ cocci and treponema pallidum

What is the mechanism of action of ampicillin, and what is it effective against?

cell wall blocker; effective against G+ cocci and treponema pallidum

What is the mechanism of action of carbenicillin, and what is it effective against?

cell wall blocker

What is the mechanism of action of cephalosporin?

blocks P. falciparum’s ability to hydrolyze hemoglobin, parasite accumulates cytotoxic levels of heme group

What is the mechanism of action of chloroquine?

antimalarial

What is chloroquine?

cell wall blocker; penicillinase-resistant penicillin

What is the mechanism of action of cloxacillin

plasma membrane blocker; good against G+ microbes; very effective against biofilms

What is the mechanism of action of daptomycin, and what is it good and very effective against?

blocks ribosomal elongation (translocation)

What is the mechanism of action of erythromycin

antifungal

What is fluconazole?

blocks sterol anabolism

What is the mechanism of action of fluconazole?

inhibition of virion entry; fuzeon binds to GP41 and blocks GP41 function

What is the mechanism of action of fuzeon? (what does it inhibit, bind, and block)

narrow-spectrum

What type of spectrum does isoniazid have?

blocks mycolic acid formation in mycobacteria

What is the mechanism of action of isoniazid?

antihelminth

What is ivermectin?

misregulation of glutamate-gated chloride channels

What is the mechanism of action of ivermectin?

cell wall blocker; penicillinase resistant penicillin

What is the mechanism of action of methicillin?

cell wall blocker; penicillinase resistant penicillin

What is the mechanism of action of nafcillin?

cell wall blocker

What is the mechanism of action of penicillin?

inhibits ribosomal protein synthesis by blocking 23s peptidyl transferase activity (impetigo)

What is the mechanism of action of pleuromutilin?

antimalarial

What is quinone?

blocks P. falciparum’s ability to hydrolyze hemoglobin

What is the mechanism of action of quinone?

transcription/mRNA synthesis blocks (anti-B-subunit)

What is the mechanism of action of rifampin?

inhibition of viral assembly; inhibition of neurominidase (N), which is needed for virion release

What is the mechanism of action of tamiflu?

blocks charged tRNAs

What is the mechanism of action of tetracycline?

sulfa drug, blocks prokaryotic PABA, which is folate anabolism (UTI infection)

What is the mechanism of action of trimethoprim?

tetracycline

What antibiotic is considered a broad-spectrum antibiotic?

any mycobacterium antibiotic (tobramycin, polymyxin); more specifically isoniazid

What antibiotic is considered a narrow-spectrum antibiotic? (Be general and specific)

interferes with the linking enzymes, cross-bridges and NAM subunits remain attached to their neighbor; the cell bursts from osmotic pressure because the integrity of peptidoglycan is not maintained

What is the mechanism of action of -cillins?

will attack NAG NAM

What is the mechanism of action of lysozymes

usually enzymatic, usually from g+ microbes

Describe secreted bacterial proteins.

lysis

How do membrane-disrupting exotoxins kill?

A = active site, B = binding

Describe A-B exotoxins.

affects neuronal transmission

What do neurotoxins affect?

intestinal cells

What do enterotoxins effect?

can affect all cells

What can cytotoxin affect?

non-specific overstimulation of host immune system, results in multi-organ failure

What are superantigens, and what do they result in?

clostridium perfingens

What Genus and species produces membrane-disrupting exotoxins?

produces exotoxins with phospholipase activity; phospholipase lyses host cells; results in necrotic tissue

Describe membrane-disrupting exotoxins produced by Clostridium perfingens.

corynebacterium diptheriae, shigella dysenteriae

What 2 Genus and species produce translation-blocking A-B exotoxins?

Tox (bacteriophage)

exotoxin gene = ?

ADP-ribosylases

exotoxins = ?

diphtheria exotoxin modifies eukaryotic EF-2 proteins; EF-2 is needed by eukaryotic ribosomes for translation elongations; results in halted protein synthesis

Describe translation-blocking A-B exotoxins produced by Corynebacterium diphtheriae.

Stx (chromosomal)

exotoxin gene = ?

A-B exotoxin with depurinase activity

STX = ?

shiga toxin removes a specific A nitrogenous base from the 28s rRNA; depurinated 28s rRNA cannot form peptide bonds; results in halted protein synthesis

Describe translation-blocking A-B exotoxins produced by Shigella dysenteriae.

clostridium botulinum, clostridium tetani

What are 2 Genus and species that produce exotoxins that inhibit nerve impulses?

botulin, neurotoxin

A-B exotoxin = ? = ? (Specifically A-B exotoxin produced by Clostridium Botulinum)

muscle contraction

What is AcH essential for?

botulin operates at the neuromuscular junction; botulin inhibits SNARE-mediated exocytosis of AC + TVs; results in flaccid paralysis; death by failure to inhale (asphyxiation)

Describe A-B exotoxins that can inhibit nerve impulses produced by Clostridium botulinum.

asphyxiation

What is the failure to inhale/exhale?

tetanospasmin, neurotoxin

A-B exotoxin = ? = ? (Specifically A-B exotoxin produced by Clostridium Tetani)

muscle relaxation

What are Glycine and GABA neurotransmitters essential for?

tetanospasmin inhibits synaptobrevin-mediated exocytosis of GABA and glycine; results in spasmic paralysis; death by failure to exhale (asphyxiation)

Describe A-B exotoxins that can inhibit nerve impulses produced by Clostridium tetani.

vibrio cholerae

What is a Genus and species that produces A-B exotoxins as enterotoxins?

CTX, cholera toxin, enterotoxin

A-B exotoxin = ? = ? = ? (Specifically when the A-B exotoxin is produced by Vibrio cholerae)

CTX modifies eukaryotic adenylate cyclase; results in massive solute efflux; osmosis ensues, enterocytes plasmolyze

Describe A-B exotoxins as enterotoxins produced by Vibrio cholerae.

A-B enterotoxins, pore-forming exotoxins, superantigen exotoxins

What types of exotoxins can Staphylococcus aureus produce?

staphylococcus aureus

What Genus and species can produce A-B enterotoxin, pore-forming exotoxin, and superantigen exotoxin?

exotoxin forms pores in the membrane causing the cytoplasmic contents to efflux and water to influx causing host cell lysis

Describe pore-forming exotoxin produced by S. aureus.

numerous activated helper T cells will hyper-activate the immune system in a non-specific fashion, patient immune system may undergo anaphylaxis

Describe superantigen exotoxin produced by S. aureus.

lipid A > pyrogenic (fever) response

endotoxin = ? → ?

macrophage eats microbe > microbe is digested releasing endotoxins > endotoxins induce macrophage release of cytokines > cytokines enter bloodstream > cytokines travel to hypothalamus > cytokines induce hypothalamus to produce prostaglandins which induce fever

What is the process of pyogenic fever response?

misregulated blood clots, leading to multiple organ failure (nutrient deprivation)

What is the 2nd way endotoxin might kill a human host, and what does this lead to?

found on the outer membrane of g- microbes

Where are the lipid portions of LPS in endotoxin found?

pyrogenic fever response

What is the 1st way an endotoxin might kill a human host?

plasma membrane of bacteria

What do both daptomycin and polymyxin attack?

obliterates phosphate heads from tails and melts the plasma membrane

What can Clostridium perfringens obliterate when it produces exotoxin?

bacterial vaginosis caused by candida spp.; lactobacillus spp. keeps candida growth in check, but antibiotics can wipe out all the lactobacilli causing candida overgrowth

Describe a possible secondary infection that might arise due to an imbalance of vaginal microflora on account of prolonged antibiotic treatment.

closely related species are inhibited by the bacteriocins

why are bacteriocins dangerous to closely related spp.?

staphylococcus lugduninsiensis

What produces lugdunin?

eleftheriae tarrae

What produces texiobactin?

yes, because toxins produced by the bacteria kill closely related species

Is lugdunin a bacteriocin, explain why or why not?

MRSA

What is one example of something S. lugduninsiensis inhibits?

no, because E. tarrae produces an antibiotic rather than inhibiting another microbe

Is teixobactin a bacteriocin, explain why or why not?

clavulanic acid

What does CA stand for?

B-lactamase inhibitor

What type of inhibitor is clavulanic acid?

bacteria that has B-lactamase will cause the beta-lactam rings on -cillin drugs to be broken down (aka hydrolyzed); this renders -cillin drugs useless; CA inhibits B-lactamase, therefore it protects the -cillin drugs from being broken down and allows them to kill bacteria they would not have been able to without the CA

How does clavulanic acid function in a synergistic fashion with certain -cillins?

since CA inhibits penicillinase it will have no effect on penicillinase-resistant penicillins; ex. methicillin, nafcillin, cloxacillin

What -cillins can clavulanic acid never synergize with, and why (give examples)?

methicillin, nafcillin, cloxacillin

What are 3 -cillins that have a beta-lactam ring, but are unaffected by beta-lactamases?

cephalosporium spp. (cephalosporin)

What is a non -cillin antibiotic with a beta-lactam ring?

beta-lactam functional group

What is this an image of?

bacteria

Are pulmonary tubercles bacteria or fungi?

fungi

Is pulmonary invasive aspergillosis a bacteria or fungi?

isoniazid, tobramycin, polymyxin, streptomycin

What are useful antibiotics against pulmonary tubercles?

any antibiotic used to treat g+ microbes; cell wall blockers (penicillins)

What antibiotics are not useful against mycoplasma?

antifungal drugs; amphotericin B

What is effective against pulmonary invasive aspergillosis?

helminth infection

What does a high number of eosinophils indicate?

parasite infection

What does a high amount of serum IgE antibody indicate?

DAS181 > influenza uses viral hemagglutinin (H) protein to adhere to host glycoproteins decorated with sialic acid residues

What is an example of an antiviral that blocks viral entry?

an enzyme that cleaves sialic acid, blocking adhesion

What is DAS181?

indinavir, saquinavir, ritonavir > HIV protease inhibitors; HIV cannot assemble without HIV protease; amatadine > inhibits the influenza M2 ion channel protein necessary for viral assembly

What are examples of antivirals that block viral genome assembly, and what is their process?

tamiflu (oseltamivir), relenza (zanamivir) > amivirs inhibit influenza neurominidase (N); N is needed for infleunza virion release as N cleaves H; sialic acid events as nascent virion buds from host plasma

What are examples of antivirals that block virion release?

hemagglutinin

What does H stand for?

neurominidase

What does N stand for?

enzyme

a single _______ can render a lot of antibiotics