chapter 10 study questions Flashcards by Meagan Strickland

which type of chemotherapy involves the use of chemotherapeutic drugs to control infection and diseases caused by many types of microorganisms

antimicrobial chemotherapy

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natural agents used only against bacterial infections

antibiotics

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three factors that should be considered before beginning antimicrobial therapy are:

the nature of the microbe causing infection, its degree of sensitivity to various drugs, and the overall medical condition of the patient

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one reason why antimicrobial sensitivity testing would be performed

is the pathogen commonly shows resistance to the antibiotic

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drug susceptibility testing for fungal infections is generally not performed b/c why

antifungals target all fungi

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the general term for the use of drugs to control infection is _______.

antimicrobial chemotherapy

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what is the minimum inhibitory concentration?

it is the highest DILUTION of a drug where it visibly inhibits growth of particular microbe

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the therapeutic index is the ratio of the _____ dose to the __________ dose that is used to assess the safety and reliability of a drug

toxic

therapeutic

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true or false

it is essential to perform a drug sensitivity test for all micros

false

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drugs that are selectively toxic should kill which cells?

microbial cells

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general mechanisms of antimicrobial drug actions

inhibiting protein synthesis
inhibiting nucleic acid structure or function
inhibiting cell wall synthesis
interference of cell membrane structure and function

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list two sites in the cell that are not primary sites of action of antimicrobial drugs in bacteria

mitochondria

golgi body

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of which of the following, which antibiotic is an inhibitor of protein synthesis?

a. quinolones
b. isoniazid
c. streptomycin
d. trimethoprim

streptomycin

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which of the following antibiotics is an inhibitor of cell wall synthesis?

a. polymyxin
b. rifampin
c. penicillin
d. tetracycline

penicillin

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which of the following semisynthetic penicillins are useful in treating infections caused by penicillinase-producing bacteria?

a. penicillin G
b. erythromycin
c. cloxacillin
d. nafcillin
e. streptomycin

nafcillin

cloxacillin

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penicillins G and V (penicillins)

used to tx gram + cocci, some gram - bacteria

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ampicillin, amoxicillin, and carbenicillin (penicillins)

broader spectrum of action, semisynthetic, use against gram neg enteric rods

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Clavulanic acid

penicillins

inhibits beta-lactamase enzymes; added to penicillins to increase effectiveness in presence of penicillinase-producing bacteria

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which bacterial enzyme makes a cell wall inhibitor ineffective?

penicillinase

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which of the following antibiotics is an inhibitor of protein synthesis?

a. tetracycline
b. rifampin
c. penicillin (cell wall)
d. polymyxin (cell membrane)

tetracycline

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most drugs that inhibit protein synthesis block the action of

ribosome

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which of the following antibiotics is an inhibitor of cell wall synthesis?

a. streptomycin (inhibit protein synthesis)
b. quinolones (inhibit rep and transcription)
c. trimethoprim (prevent folic acid synthesis in cytoplasm)
d. cephalosporin
d. rifampin (inhibition of RNA polymerase)

d. cephalosporin

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which of the following antibiotics inhibits translocation of the ribosome subunit during translation?

a. penicillin (blocks cell wall production)
b. erythromycin (protein synth inhibitor on 50S subunit)
c. tetracycline
d. streptomycin

erythromycin

not tetra b/c: while it does stop protein synthesis, it blocks attachment of new amino acids, not movement of the ribosome on the mRNA

not strepto: results in abnormal proteins, but does not block production of proteins

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by blocking enzymes required for the synthesis of tetrahydrofolate, _________ interfere with folate metabolism

sulfonamides

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to treat Pneumocystis infections in _________ patients, | __________ is used in combination with sulfamethoxazole

AIDS/HIV | trimethoprim

antibiotics that affect nucleic acid synthesis specifically affect the processes of replication and __________

transcription

which antibiotic specifically inserts on sites of the 30S subunit of prokaryotic ribosomes causing the misleading of mRNA and thus inhibit translation?

aminoglycosides

trimethoprim and sulfamethoxazole are often given in combo because of ___________ effect together

synergistic

polymyxins work by interacting with what component of the cell membrane causing leakage

phospholipids

cephalosporins are broad or narrow

broad

erythromycin inhibits __________ of the ribosomal subunit during translation

translocation

antibiotic that specifically inserts on the sites of 30S subunit of prokaryotic ribos causing misreading og mRNA and inhibits TRANSLATION

aminoglycosides (streptomycin)

cephalosporins have the same effect as

penicillins

used by patients who are allergic to pencillin

Aztreonam

biofilm bacteria are not affect in the same way as their free-living counterparts because the biofilm bacteria express different

genes

tetracyclines inhibit protein synthesis by blocking attach of _______ on the A receptor site

tRNA

drugs that are effective against fungi are likely to be toxic to _______ because they are both eukaryotes

humans

glycylcyclines are newer derivatives of

tetracyclines

quinine is a drug used to treat

protozoal infections; extracted from bark; MALARIA

Ivermectin and praziquantel are never drugs used for tx of

helminthic infections

identify three major modes of action an antiviral drugs

preventing virus maturation barring virus penetration into host cell blocking virus transcription and translation

OG drug used for malaria

quinine

adaptive response in which microorganisms begin to tolerate an amount of a drug that would ordinarily be inhibitory is called

drug resistance

drug resistance arises when

an organism gains the genetic info for resistance from another organism spontaneous mutation occurs in the organisms DNA code

bacterial cells described as persisters are resistant to antibiotics b/c they

can slow or stop their metabolism in the presence of a drug

in some fungi, a small regulatory RNA know as interfering RNA can temporarily silence a gene. When this gene encodes ___________, the fungus is transiently resistant to the antibiotic

the target of the antibiotic

epigenetic mechanisms of antibiotic resistance in fungi are

reversible | ***think interfering RNA: temporary

drug resistance genes found on the bacterial chromosome usually result from

spontaneous mutation

An ______ factor is a type of plasmid that confers antibiotic resistance

horizontal transfer originates from plasmids called resistance R factors that are transferred through

conjugation, transformation, or transduction

mechanisms of drug resistance

new enzymes are synthesized, inactivating the drug permeability or uptake of the drug into the bacterium is decreased drug is immediately eliminated (acquisition of new genes) binding sites for drugs are decreased in number or affinity an affected metabolic pathway is shut down or an alternative pathway is used

a concerning development is the identification of the mcr-1 gene which renders bacteria resistant to the last-resort antibiotic __________

polymyxin

CRISPR has been used to tx antibiotic-resistant infections by directing specific gene cuts to

the antibiotic resistant genes

preparations of live microbes used as a preventative or therapeutic measure to displace or compete with potential pathogens are called

probiotics

categories of major drug side effects

normal flora disruption toxicity to tissues allergic reactions

mcr-1 gene

resistant to polymyxin BAD- threat

bacterial system that can be used to cause very specific cuts is genes is termed

CRISPR

a drug _____ occurs when a drug acts as an antigen and stimulates an immune response

allergy

antimicrobial drug damage can be

permanent or reversible

problems that have led to the worldwide problem of managing antimicrobial drugs

shot gun approach by doctors increase in superinfection development of resistance in "bystander" microbes

t or f | most tissues can be affected by adverse effects caused by use of antimicrobial therapy

TRUE gastro, cardiovascular, nervous, resp, skin, and bones can all be affected

the human _____ is the sum total of al microbes found on and in a normal human

microbiome

some microbes associated with the body that can be rapidly lost, for example when hand washing, are termed

transients