chapter 11 pt 2

Question 1

aminoglycosides

Answer 1

interfere w proteins
-bind to 30s subunit so the mRNA gets misread cause frameshift
-inhibit protein synth
-useful for aerobic gram negativie robs and some gram positive bacteria

Question 2

which microbes make aminoglycosides

Answer 2

streptomyces and micromonospora

Question 3

tetracyclines

Answer 3

block protein synthesis by binding to 30S subunit and preventing aminoacyl trna from binding to mrna ribosome complex

Question 4

chloramphenicol

Answer 4

blocks peptide bond formation and protein synthesis
-synthetic
-TOXIC

Question 5

why is chloramphenicol toxic?

Answer 5

inhibits mitochondrial ribosomes

Question 6

macrolides

Answer 6

erythromycin

Question 7

erythromycin

Answer 7

goes to 50S subunit and prevents ribosome translocation so cant move onto mRNA

Question 8

erythromycin drugs

Answer 8

-zithromax, azithromycin and z pack
-low toxicity and broad spectrum

Question 9

fluoroquinolones

Answer 9

bind to DNA gyrase and topoisomerase IV so bacterial DNA cant replicate

Question 10

fluoroquinolone drugs

Answer 10

-ciprofloxacin
-broad spectrum

Question 11

why does fluoroquinolone use have to be monitored

Answer 11

because overuse can lead to ciprofloxacin resistant bacteria

Question 12

what are most drugs that block metabolic pathways?

Answer 12

synthetic

Question 13

what is the most important metabolic pathway blocker?

Answer 13

sulfonamides/ sulfa drugs

Question 14

how do sulfas work

Answer 14

-competitive inhibition
-block enzyme needed for folic acid synthesis
-narrow spectrum
-bacteriostatic (stops growth no KILL)

Question 15

golden age of antibiotics

Answer 15

1940 - 1980

Question 16

antibiotic classes

Answer 16

penicillins, tetracyclines, macrolides, fluoroquinolones, carbapenems

Question 17

resistance

Answer 17

reduced effectiveness of antimicrobial drug

Question 18

how does resistance arise?

Answer 18

genetic versatility, an aquired mutation, intrinsic/ natural resistance mechanism that existed before it was exposed to the drug

Question 19

example of intrinsic natural resistance mechanism

Answer 19

a gram positive drug can’t affect a gram negativie drug

Question 20

where are spontaneous mutations coming from?

Answer 20

chromosome genes
-can transfer from species to species bc it comes from resistance factor int he plasmid that transposons

Question 21

natural selection

Answer 21

eventually the population will be resistant bc the non resistance cells are destroyed
-this does not happen until exposure to the drug occurs

Question 22

MRSE

Answer 22

methicillin resistant staphylococcus aureus
-resistant to many antibiotics
-most are skin infections in community

Question 23

MRSA in hospital

Answer 23

life threatening sepsis, pneumonia or surgical site infection

Question 24

steps to reduce drug resistance

Answer 24

-accurate diagnosis and drug
-compliance to correct dosage for the required time
-multidrug therapy

Question 25

why should u take the entire dosage of the drug for the right time?

Answer 25

because this will diminish the selection for mutations that can lead to low drug level resistance bc not all pathogens are eliminated

Question 26

goal of drug research

Answer 26

-short term higher dose antimicrobials that are effective and less expensive with less side effects

Question 27

possible long term solution to resistance

Answer 27

adding antimicrobials to animal feed worldwide

Question 28

assay for drugs that are commonly resistant

Answer 28

Kirby Bower disk diffusion test -will test for resistance

Question 29

dilution test

Answer 29

minimum inhibitory concentration test to show the smallest concentration of drug that will VISIBLY inhibit growth

Question 30

MIC

Answer 30

minimum inhibitory concentration -smallest amount to stop microbe growth -goal: clear tube

Question 31

therapeutic index

Answer 31

ratio of the dose of the drug that is toxic to humans compared to its minimum effective dose

Question 32

what type of index is desired

Answer 32

high index

Question 33

drug resistant strain found in eye drops

Answer 33

P aeruginosa -this is NOT all around us

Question 34

listeria monocytogenes

Answer 34

-gram positive -doesnt form spores -short (cocobacilli) or long filaments -form flagella out of the body (1-4) -no capsules

Question 35

what is listeria monocytogens resistant to?

Answer 35

heat, cold, salt, ph, bile

Question 36

where is listeria monocytogens found

Answer 36

in the fridge -it is a psychotroph