Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

FM2 > Protein/ DNA Inhibiting Antibiotics > Flashcards

Protein/ DNA Inhibiting Antibiotics Flashcards

(96 cards)

Start Studying
1
Q

Prokaryote ribosomes contain __ and __ subunits

A

30S, 50S

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

List two antibiotic groups that target the 30S ribosomal subunit

A

aminoglycosides

tetracyclines

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

List five antibiotic groups that target the 50s ribosomal subunit

A

macrolides
clindamycin
streptogramins
chloramphenicol

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

List one antibiotic that targets formation of the 70S initiation complex

A

Linezolid (an oxazolidinone)

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

List natural and semisynthetic aminoglycosides

A

Natural: gentamicin, neomycin, streptomycin, tobramycin

Semi-synthetic: amikacin (kanamycin + hyroxy butyric acid)

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

Describe the spectrum of activity of aminoglycosides

A

Enterobacteriacaea: Escherichia, Klebsiella, Enterobacter, Serratia, Proteus, Staphylococci
Tobramycin and amikacin specifically have activity against Pseudomonas

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

List organisms NOT covered by aminoglycosides

A

Streptococci
Enterococci
Anaerobes- lack oxygen dependent active transport into cell

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

How can aminoglycosides be useful in streptococcal or enterococcal infections?

A

Combination with beta lactam- usually gentamicin

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

List the two aminoglycosides that are most effective against mycobacteria

A

Streptomycin

Amikacin

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

Aminoglycosides show ___ dependent killing; prolonged_____ effects; and are best dosed __x per day

A

concentration
postantibiotic/ persistent
high doses 1x daily

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

List mechanisms of resistance against aminoglycosides

A

enhanced efflux
inactivating enzymes (transposable genes on plasmids)
chromosomal mutation- only with streptomycin and TB

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

Amikacin has less resistance than other aminoglycosides because it is inactivated by one enzyme, whereas ___ can be inactivated by 8 enzymes

A

Kanamycin

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

Aminoglycosides show ___ oral absorption, distribution in ECF, CNS penetration

A

Poor

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

Describe the two major adverse effects of aminoglycosides

A

Nephrotoxicity- reversible because renal tubular cells can regenerate. caused by drug entering from urine side of cell through pinocytosis. saturable kinetics, so less effect with 1x daily dosing

Ototoxicity- irreversible, hair cells are not regenerated

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

In order to cause nephrotoxicity, aminoglycosides must first bind to _____ on the brush border of renal tubular cells. this exhibits ____ kinetics

A

Megalin

Saturable

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

List the major clinical uses for aminoglycosides

A

Plague
Tularemia
Complicated UTI with GNRs
Combined with B lactams for Psedomonas, staph, strep, enterococcal infections like endocarditis
Surgical prophylaxis
Mycobacteria (second line, always in combination)

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

List two semisynthetic tetracyclines and one glycylcycline

A

Doxycycline, minocycline

tigecycline

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What advantages does tigecycline have over semisynthetic tetracyclines?

A

Blocks efflux from cells

Binds better to ribosomes

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

Describe the spectrum of activity of tetracyclines

A

Gram positives, gram negatives, mycoplasma, chlamydia, rickettsia, spirochetes, malaria

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

Tetracyclines have poor activity against ____ and ______

A

enterococci

Pseudomonas

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Minocycline and tigecycline are better than doxycycline against _____

A

MRSA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Why are tetracyclines bacteriostatic?

A

Binding to 30S is reversible

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Tetracycline killing is __ dependent

A

time

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

List mechanisms of resistance for tetracyclines

A

Drug efflux
Ribosomal protection
extensive cross resistance but does not apply to glycylcyclines like tigecycline

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Tetracyclines have ___ oral absorption, tissue distribution, intracellular concentrations
good
26
List adverse effects of tetracyclines
Discoloration of teeth and bones- do not use in children, pregnant women GI problems- NVD, take with food Superinfection- oral and vaginal candidiasis
27
List clinical uses of tetracyclines
``` STIS Borrelia Ehrlichia CAP Rickettsia Falciparum malaria Anthrax MRSA ```
28
How can chloramphenicol be inactivated?
acetylation of nitro group
29
Chloramphenicol is _______ because of reversible binding
bacteriostatic
30
Describe the spectrum of activity of chloramphenicol
Broad spectrum Poor activity against legionella and pseudomonas
31
Resistance to chloramphenicol is due to production of ________________ which acetylates the nitro group
Chloramphenicol acetyl transferase
32
Chloramphenicol has ____ oral bioavailability and extensive distribution because of high ____ solubility
Excellent | Lipid
33
List adverse effects of chloramphenicol
Bone marrow suppression (reversible) Aplastic anemia, rare and non-reversible Gray syndrome in neonates
34
Describe the clinical use of chloramphenicol
Serious salmonella, typhoid fever in developing countries in developed countries- bacterial meningitis if penicillin allergy, anaerobic infections in CNS
35
List one natural and two semisynthetic macrolides
Natural: erythromycin Semi-synthetic: clarithromycin, azithromycin
36
Describe the spectrum of activity of macrolides
Streptococci, pneumococci Legionella, Mycoplasma, Chlamydia Helicobacteria some atypical mycobacteria
37
Macrolides have weak activity against hemophilus influenzae because hemophilus has an _________
efflux pump
38
List mechanisms of resistance for macrolides
Methylation of 23s ribosome RNA- Europe, Erm genes Enhanced efflux pumps- USA, mef genes Chromosomal mutation of 50S Drug inactivation
39
Erythromycin has modest oral absorption because it is _____ in the GI tract, but azithromycin and clarithromycin are better absorbed because they are more _________
ionized acid stable
40
List adverse effects of the macrolides
GI intolerence Hepatitis in pregnant women Ototoxicity, reversible
41
Describe clinical use of macrolides
respiratory infections (sinusitis, otitis, pneumonia, bronchitis, DOC for CAP) Strep pharyngitis and cellulitis if penicillin allergy Atypical mycobacteria esp MAC Helicobacter pylori, in combination with PPI Pseudomonas exacerbations in CF (azithromycin)
42
Why is azithromycin effective in Pseudomonas infections in people with CF?
Azithromycin is effective in biofilms but has no direct effect on Pseudomonas
43
______ is a lincosamine antibiotic
Clindamycin
44
Clindamycin is active against...
Staphylococci, streptococci, anaerobes incl bacteroides fragilis moderate activity against toxoplasma, pneumocystis poor activity against mycoplasma, chlamydia, legionella
45
Resistance to macrolides and clindamycin suggests presence of ___ genes Resistance to macrolides but susceptibility to clindamycin suggests presence of ___ genes
Erm Mef Clindamycin resistance is similar to macrolid resistance but clincamycin is not effluxed
46
Clindamycin has ____ oral bioavailability and extracellular / intracellular distribution
good
47
List two adverse effects of clindamycin
diarrhea | pseudomembranous colitis
48
Describe clinical uses of clindamycin
anaerobic infections above the diaphragm Strep (+ penicillin) Staph (incl MRSA, better than macrolides) alternate option for toxoplasmosis and pneumocystis
49
______ was the first oxazolidonone antibiotic; ____ is a newly released oral option.
Linezolid | Tedizolid
50
Linezolid binds to the 50S ribosome and inhibits formation of the __
70s initiation complex
51
Describe the spectrum of activity of linezolid
Broad: staph, MRSA, strep, pneumococci, enterococi
52
Linezolid is considered _______ but it does kill bacteria slowly
bacteriostatic
53
Linezolid resistance is seen primarily in ___________ and is very rare but increasing in Staph aureus
Enterococcis faecium; resistance due to mutations near binding site of ribosome
54
Linezolid has excellent ____ penetration and very good distribution to the ______ tract
CNS | respiratory
55
List adverse effects of linezolid
thrombocytopenia and anemia | peripherla neuropathy
56
List clinical uses for linezolid
VRE MRSA MRSE CNS effects due to MRSA or MRSE
57
_____ is a _____ antibiotic that is a combination of dalfopristin (A) and quinupristin (B).
Synercid | streptogramin
58
When used alone, the streptogramins are ___; when used together they are ______
bacteriostatic | bactericidal
59
Streptogramins have good activity against __________ and no activity against _________
Staph, strep, enterococcus faecium no activity against e fecalis
60
List clinical use of streptogramins
VRE (e faecium only) MRSA not commonly used due to adverse reactions
61
List adverse reactions to streptogramins
Phlebitis | myalgias/ arthralgias
62
______ is an antibiotic that binds to proteins involved in protein synthesis and is used in urinary tract infections
nitrofuratoin
63
Nitrofurantoin works by ________ producing reduced derivatives that interfere with protein synthesis
nitrofuran reductase
64
Resistance to nitrofurantoin is due to ____
reduced nitrofuran reductase activity
65
List two adverse effects of nitrofurantoin
GI | Pulmonary hypersensitivity
66
Describe the clinical use of nitrofurantoin
Treatment and prophylaxis of UTI not effective in patients with less than 50% of normal renal function- can’t get enough active drug into urine, will be metabolized and removed
67
List five nucleic acid synthesis inhibitors
``` quinolones rifampin metronidazole trimethoprim sulfonamides ```
68
List two quinolones
ciprofloxacin | moxifloxacin
69
Fluoroquinolones work by inhibiting ________, enzymes involved in supercoiling of DNA
DNA gyrase/ topoisomerase II | Topoisomerase IV
70
Quinolones are ______ and show ____ dependent killing
bactericidal | concentration dependent
71
_____ is the only oral drug active against Pseudomonas
ciprofloxacin
72
norfloxacin and ciprofloxacin are active against ________
aerobic gram negative bacilli
73
Moxifloxacina nd gemifloxacin have increased activity against:
Gram positive cocci atypical respiratory pathogens mycobacteria
74
List mechanisms of resistance to fluoroquinolones
Mutation of DNA gyrase mutation of topoisomerase decreased permeability-altered porins enhanced efflux pumps
75
Describe fluoroquinolone pharmacology
Excellent oral bioavailability Very good serum and tissue concentrations Norfloxacin, ciprofloxacin and levofloxacin eliminated primarily in the urine Moxifloxacin and gemifloxacin eliminated primarily by liver
76
List adverse effects of fluoroquinolones
``` Cartilage damage, achilles tendon rupture phototoxicity hepatitis QTc prolongation dizziness dysglycemias ```
77
List clinical uses of fluoroquinolones
Serious gram - infections including Pseudomonas Enteric infections Respiratory infections- CAP, HAP, DOC for legionella Mycobacterium UTI esp pyelonephritis Prostatitis Anthrax
78
Rifampin works by inhibiting ______________
DNA dependent RNA polymerase; acts on beta subunit
79
Rifampin is _______
bactericidal
80
List spectrum of activity for rifampin
MSSA, MRSA, mycobacteria
81
List spectrum of activity for rifaximin
noninvasive E colin in gut, C diff
82
Resistance to rifampin is due to ____ and is very common
mutation of beta subunit of RNA polymerase
83
Rifampin has excellent oral bioavailability but ____ does not, so it is used for infections within the bowel
Rifaximin
84
List adverse effects of rifampin
hepatitis drug interactions- P450 enzyme inducer orange discoloration of urine
85
List clinical uses of rifampin
Mycobacterial infections, MAC | Staphylococcal infections in combination with beta lactams (active in biofilms)
86
List clinical uses of rifaximin
traveler's diarrhea | relapsing C diff
87
Describe mechanism of action of metronidazole
converted to active metabolite by reduction of nitro group, binds to and damages DNA
88
Describe metronidazole spectrum of activity and resistance
Activity: Bacteroides fragilis, C diff, entamoeba, giardia, trichomonas vaginalis Resistance: organisms that lack nitro reductase activity
89
Describe metronidazole pharmacology
Good oral bioavailability (very lipid soluble) Excellent tissue distribution including CSF Eliminated primarily by the liver
90
Describe adverse effects of metronidazole
Peripheral neuritis | vomiting with alcohol
91
Describe clinical use of metronidazole
Anaerobic infections below the diaphragm C diff Protazoan infections- entamoeba, giardia, trichomonas
92
_______ inhibits dihyrdopteroate reductase and ______ inhibits dihydrofolate reductase
Sulfonamides Trimethoprim
93
Describe spectrum of activity of sulfonamides and trimethoprim
Sulfonamides: nocardia, toxoplasma, pneumocystis Trimethoprim: E coli, Klebsiella, staph, pneumococci, pneumocystis
94
List adverse effects of sulfonamides and trimethoprim
sulfonamides: rash, crystals in urine trimethoprim: folate deficiency
95
List clinical uses of TMP-sulfa
UTI, respiratory infections, pneumocystis, typhoid fever, enteric infections, MRSA, nocardia, toxoplasmosis, burns
96
List oral drugs that are active against CA-MRSA
Doxycycline (Minocycline) Clindamycin- particularly for children, less risk of C diff Linezolid – very expensive Moxifloxacin- covers less than 50% of strains Rifampin (never use alone) TMP/SMZ

FM2 (11 decks)

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