Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

M & D > Ch 14: Antimicrobial Drugs > Flashcards

Ch 14: Antimicrobial Drugs Flashcards

(49 cards)

Start Studying
1
Q

Antibiotic

A

a substance produced by living organisms which kill or inhibit the growth of bacteria

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

antimicrobial agent

A

a chemical whch is synthesized to kill or inhibit the growth of bacteria or microorganims

there are also anti-viral, anti-fungal, anti-protozoan compounds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

bacteriostatic

A

compound inhibits the growth of bacteria without killing it as long as it is present

(when the compound is removed the bacteria can grow again)

prolonged exposure can lead to death by the immune system killing them

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

bactericidal

A

if enough of the compound is absorbed by the bacteria they are killed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Wide spectrum

A

active against many types and groups of bacteria

ex/ gram positives and Gram negatives => BOTH

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

narrow spectrum

A

active agaisnt few types of only one group of bacteria
ex/ only Gram-positives or only Staphylococcus

most narrow spectrums work against Gram +

antibiotics against gram negatives are very rare. Most antibiotics that target them are wide spectrum, killingh off both gram + and - bacteria

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

MIC

A

minimal inhibitory concentration

lowest concentration of an antibiotic whihc stops the growth of that species of bacteria under the conditions tested

important because the higher the dose of an antibiotic the worst the side effects

common

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

MLC

A

minimal lethal concentration

lowest concentration of an antibiotic which kills all the bacteria (of that species)

not as common as MIC

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

AUC

A

area under the curve

integrated time where in vivo concentration of the antibiotic is greater than the MIC

if drug is dosed by time interval there will be spikes in concentration of the drug in the blood and troughs as teh drugs is eliminated

want to maintain the concentration of the drug in the blood above the MIC

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Therapeutic index

A

the ratio of the dose of the antibiotic whihc is toxic to a human to the dose whihc is effective at inhibiting of killing the bacterium

a measurement of selective toxicity

toxic to bacteria but not to humans

the higher the therapeutic index, the more useful the antibiotic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

good and bad MIC range

A

good
=> 1mg/ml

really good 0.1/0.05 or less
=> fluroquinolines and some penicillines agaisnt gram + and streptococci

with pseudomonas aerginosa, can be upwards of 16

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Oral administration of antimicobials

A

rug must be acid stable, absorb through the stomach or intestines

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

parenteral administration of antimicrobials

A

intraventous or intramuscular

drug acid labile or unable to absorb through GI tract

drug may be sparingly soluable - need continuous infusion

maintains higher concentration in blood/ tissue

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Targets of antibiotics

A

antimetabolites (metabolism)

inhibition of cell wall (peptidoglycan) synthesis

inhibition of DNA/RNA biosynthesis

Inhibition of protein biosynthesis

Inhibition of energy production

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Antimetabolites

A

compounds which interfere with cellular metabolism
=> mostly the small molecule metabolism

the only commercially available antimetabolite are the sulfoanamides (sulfa drugs)

really not antibiotics - synthetic chemicals
=> discovered by extension of Ehrlich’s search for a magic bullet screening of organic chemicals

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Sulphanilamide

what does it do

A

competitive inhibitor of p-aminobenzoic acid and prevents the incorporation of p-ABA into folic acid

folic acid is a co-factor in many essential enzymes including C1 metabolism needed for the biosynthesis of purines, pyrimidines, methionine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Bacterial targets of Sulphanilamide

A

broad spectrum antimicrobial agents

GAS
Strep pneumonia
Staphylococci
Neisseria spp
Haemophilus influenzae
Bordetella pertussis
Yersinia pestis
Chlamydia spp
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

The use of Sulphanilamide today

A

the use of sulphonamides is now limited by widespread resistance in bacteria and toxicity

most common sulfa drugs now used are sulfisoxazole and sulphamethoxale

use is restricted to treating UTIs

Dapsone- the main drug used in leprosy treatment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Inhibition of cell wall biosynthesis

A

most important target is peptidoglycan biosynthesis

most important inhibitors of peptidoglycan synthesis are the beta-lactams

penicillin was discovered in 1928 by Fleming
=> observed lysis of Staphylococcus colonies on a plate contaminated with mold (penicilliium notatum) (today penicillum crysogenmum is used commercially)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Bacterial targets of penicillin

Study These Flashcards
A

Fleming demonstrated the culture broth had antibacterial activity against

Staphylococci
Streptococcus pneumoniae
Nisseria meningitidis
Neisseria gonorrohoeae

but not against most Gram-negative bacteria

21
Q

Penicillins G, V and semi-synthetics

Study These Flashcards
A

Natural penicillins (G and V) are only active against Gram-positive bacteria (V is more acid labile- can take orally, cant do this with G)

semi-synthetic penicillins developed to oversome beta-lactamases

  • methicillin (the M in MRSA)
  • oxacillin (the form used in N. America)
  • cloxacillin (or dixloxacillin)
  • flucloxacillin
22
Q

Broad spectrum penicillins (amino penicillins)

Study These Flashcards
A

increased activity against Gram-negative bacteria

still active against Gram-positives

acid stable, oral

amocicillin, ampicillin

23
Q

Penicillins active against Pseudomonas aeruginosa

Study These Flashcards
A

ticarcillin, carbenicillin

also the extended spectrum penicilllins such as piperacillin

beta lactamase resistant penicillins

temocillin

24
Q

Cephalosporins

Study These Flashcards
A

chemically related to penicillin

beta lactam- dihydrothiazine rings

inhibit the same target as penicillin

wide spectrum of activity compared to penicillin

resistant to Staphylococcus Beta-lactamase

cephalosporin C original, base for semi-synthetic antibiotics

over 25 different ones now in use

25
First generation cephalosporins
cephaloridine was the first cephalosporin => cefadroxil, cephazolin effective against S. aureus and penicllin resistant S. aureus effective against teh streptococci and enterococci effective against E. coli, Klebsiella pneumoniae, and proteus mirabilis
26
Second generation cephalosprins
cefoxitin resistant to gram negative beta lactamases wider spectrum of activity Haemophilus, enterobacter
27
Third generation cephalosporins
effective against pseudomonas aeruginosa, almost all Enterobacteriaceae, Neisseria gonorrhoeae ceftriaxone, cefotaxime
28
Fourth generation cephalosporins
Gram positives and more Gram negatives better against beta lactamase prodducers cefeprime
29
Fifth generation cephalosporins
designed to be effective against beta lactamase producers and MRSA ceftolazane (2014), ceftaroline (2010), ceftobiprole (2016)
30
Monobactams
Just a beta lactam ring, used against Gram-negative bacilli axtreoman
31
Carbapenems
very wide spread activity active against beta lactamases and ectended spectrum beta lactamases (ESBL) doripenem, ertapenem, imipenem, meropenem => antibiotics of last resort
32
problems with beta lactam antibiotics
dont cross the blood-brain barrier and do not generally penetrate cells
33
Vancomycin
glycopeptide also blocks transpeptidation by binding to the terminal d-ala-d-ala part of the pentpeptide of the peptidoglycan precursor bactericidal, narrow-spectrum- gram-positives cocci and bacilli was antibiotic of last resort for MRSA and enterococci New glycopeptides - dalbavancin, oritavancin, telavancin
34
Inhibition of protein biosynthesis aminoglycosides
inhibits elongation and icreases mis-reading of mRNA bactericidal broad-spectrum => Gram-positives, Gram-negatives and mycobacterium often used iwth Beta lactams for synergy primary use is for treating Gram-negative and Peudomonas aeruginosa infections
35
Aminoglycosides
inhibite protein biosynthesis 3-4 sugars, some substituted with amino groups
36
different aminoglycosides and their uses
streptomycin = antiTB Gentamycin = anti-pseudomonad tobramycin = replacement for gentamycin neomycin = toxic, use in topical treatment kanamycin= enterics but not PA Amikacin = semi-synthetic, resistant to inactivating enzymes plazomicin = new (2018)
37
why are less people allergic to penicillin today
the ways we make penicillin are more pure, and there is less junk that causes the allergy
38
Tetracycline
introduced in 1948 bacteriostatic blocks binding of amino-tRNAs to ribosomes wide-spectrum staph and strep but not enterococci Gram-negatives except PA and some enterics mycoplasma Clamydia and Rickettsia Spirochetes => BOrrelia burgoferii
39
Tetracycline uses
used to treat respiratory and urinary tract infections used to treat many STDs used to treat intracellular bacteria newer tetracyclines => doxycyclines, minocycline => tigecycline =>omadacycline, eravacycline, sarecycline
40
Macrolides
inhibition of protein biosynthesis a very large lactone ring with attached sugars 14 or 16 C atoms int eh ring bacteriostatic wide spectrum of activity mostly used as an alternative to penicillins for penicillin-sensitive patients mostly used to treat Gram-positive infections antibiotic of choice for whooping cough (bordetella pertusis) and legionaires disease (legionella pneumophillia)
41
What bacteria are macrolides used against
antibiotic of choice for whooping cough (bordetella pertusis) and legionaires disease (legionella pneumophillia) used to treat community acquired pneumonia streptococcus pneumoniae haemophilus influenzae maraxella cararrhalis used to treat mycoplasma and chlamydia infections erythromycin and azithromycin
42
Inhibitiion of DNA biosynthesis
most important are teh fluroquinolones the first quinolone antimicrobial was naladixic acid effective only against Gram-negatives (RARE) used to treat UTIs (it is concentrated in the urine by the kidneys) ``` by adding a flurine atom to the C6 of the quinolone ring a new class of antimicrobials => the fluroroquinolones ```
43
decantination of DNA
done by DNA topoisomerase fluroquinolone target
44
What are the fluroquinolones effective against
most Gram-negatives including Pseudomonas aeruginosa and some Gram-positives staph, strep pneumoniae and enterococcus
45
second generation fluroquinolones
ciprofloxacin
46
third generation fluroquinolones
moxifloxacin imporve activity against Gram positives activity against some anaerobes and atypical bacterial pathogens used to treat respiratory tract infections, virtually any bacterium and more severe cases except MRSA better MIC against gram negatives some of the best antibiotcs we have
47
mocifloxacin
thrid generation fluroquinolones imporved activity agaisnt gram-positives activity against some anaerobes and atypical bacterial pathogens used to treat respiratory tract infections, virtually any bacterium and more severe cases except MRSA
48
Rifampin or rifampicin
inhibitionof RNA biosynthesis rifampin mainly used for TB treatment as part of a multi drug program used for prophylaxis against Neisseria meningtidis and Haemophilus influenzae menigtitis outbreaks
49
problems with fluroquinolones
prolonged usage can be problematic tendon thinning and some neurological problems

M & D (18 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions