Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

M(ASCP) Prep > Antibiotics/Resistance > Flashcards

Antibiotics/Resistance Flashcards

1
Q

Aminoglycoside concerns

A

Ear and kidney toxicity

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

Aminoglycoside mechanism

A

Aminoglycosides bind irreversibly to bacteria 30S and 50S ribosomal subunits to prevent initiation complex formation + protein synthesis BacterioCIDAL

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

Aminoglycoside spectrum

A

Primarily effective against GRAM NEGATIVES but synergistic with beta-lactams for G+

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

2 drugs commonly used for anaerobes

A

Metranidazole or clindamycin

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

Nucleic acid synthesis inhibitor used for cryptococcus meningitis

A

5-FC

Bone marrow toxicity and resistance can develop in days so always use in combination

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

Antifungal with ability to form pore in cell wall

A

Amphotericin B

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

Azole mechanism

A

Inhibition of cytochrome P-450 to block synthesis of ergosterol

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

Echinocandins do not work on…

A

Zygomycetes

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

Target of echinocandins

A

Block B-1,3-glucan synthase inhibitors

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

Good drug for mycoplasma (no cell wall)

A

Azithromycin (Macrolide)

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

Classes of beta-lactams

A
  1. Penicillins 2. Cephalosporins 3. Monobactams 4. Carbapenems
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Common concern for treating patients with beta-lactams

A

Allergies (mild to anaphylaxis)

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

Beta-lactam mechanism

A

inhibits cell wall synthesis by binding to and preventing PBP function of cross-linking NAM and NAG BacterioCIDAL

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

Ceftriaxone is what generation cephalosporin?

A

3rd

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

Cefezolin is what generation cephalosporin?

A

1st often used as surgical prophylaxis

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

Subclasses of cephalosporins

A
  1. Classified from 1st to 5th generation 1st narrow spectrum (G+) 5th broad spectrum and better with G-
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Clindamycin limitations

A

Poor penetration into CSF –> don’t use for meningitis

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

Clindamycin mechanism

A

Bind 50S ribosomal subunit, prevents elongation of peptide chains—suppresses protein synthesis (same spot as macrolides) Can be bacteriostatic or bacteriocidal

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

Fluoroquinalone spectrum with increasing generation

A

Early better for G- Later better for G+

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

First gen fluoroquinalone

A

Nalidixic acid

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

Third gen fluoroquinalone

A

tosufloxacin

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

Second gen fluoroquinalones

A

Ciprofloxacin and levofloxacin

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

Fourth gen fluoroquinalones

A

Moxifloxacin and Gemifloxacin

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

Fluoroquinolone mechanism

A

Inhibit DNA gyrase +/- topoisomerase IV to inhibit chromosomal replication BacterioCIDAL

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Leuconostoc has intrinsic resistance to what antibiotic
Vancomycin
26
Klebsiella isolate resistant to aztreonam and ceftriaxone has what resistance mechanism?
K-1 beta lactamase
27
Macrolide side effects
GI distress
28
Macrolide spectrum
Broad-spectrum: Gram positives, some Gram-negative, anaerobes, atypical mycobacteria, and “atypical” respiratory pathogens (mycoplasma, chlamydiae, Legionella) that are less susceptible to β-lactams
29
Macrolides mechanism
Bind reversibly to 23S of rRNA of the 50S ribosomal subunit, block translocation of tRNA from acceptor to donor side on ribosome BacterioSTATIC
30
A predefined stable antibiotic gradient is present on a thin carrier strip.
E-test
31
A paper disk with defined amount of antibiotic is used to generate a dynamically changing gradient of antibiotic concentrations in the agar in the vicinity of the disk. ZOI gives qualitative indication if whether the bug is susceptible.
Kirby-Bauer Method
32
the lowest concentration of an antimicrobial that will kill an organism.
MBC = Minimum Bactericidal Concentration
33
What density should the inoculum for Kirby-Baur tests be?
0. 5 McFarland 1. 5 x 108 organisms/mL
34
the lowest concentration of an antimicrobial that will inhibit the visible growth of a microorganism after overnight incubation.
MIC = Minimum inhibitory concentration
35
Metronidazole coverage
Requires reduction of nitro group under anaerobic conditions, therefore only effective against anaerobes and protozoa
36
Metronidazole mechanism
Causes breaks in DNA
37
Beta-lactam resistant to β-lactamases. Purely Gram-negative coverage, primarily active against members of the family Enterobacteriaceae
Monobactams
38
Polymixin concerns
Kidney and neurotoxicity
39
Polymixin uses
Primarily for multi-drug resistant Gram negatives (eg. Pseudomonas) Also used as a topical Ab with no toxicity concerns
40
Polymixins mechanism
Large polypeptides with cationic detergent effect that disrupts cell membrane
41
AmpC characteristics
Not inhibited by bet-lactamase inhibitors
42
AmpC mechanism
Cascade triggered by the sensing of damage to the cell wall. Induces AmpC expression, a beta-lactamase
43
Name the SPICEM organisms and what resistance patten they can carry
SPICEM organisms are members of the Enterobacteriaceae that often carry an inducible AmpC gene * Serratia * Providencia * Indole-positive Proteus (vulgaris) * Citrobacter * Enterobacter * Morganella
44
Transferrable carbapenemase
KPC
45
Carbapenemase detection
Hydrolysis of immipenem Modified Hodge test- test isolate produces the enzyme and allows growth of a carbapenem susceptible strain towards a carbapenem disk
46
Resistance to carbapenems caused by...
Efflux or carbapenemase
47
Erythromycin and Clindamycin resistance mechanism
Methylation of 50S ribosome
48
Erythromycin/Clindamycin resistance detection
D-zone test
49
ESBL characteristics
Sensitive to beta-lactamases
50
General mechanisms of antimicrobial resistance
Efflux pumps Restricted access to target Target modification Inactivating enzymes
51
Mechanism of MRSA
mecA gene encodes an altered penicillin-binding-protein, PBP2a, that beta-lactams cannot bind to. Often on a mobile element, SCCmec, so there are concerns for spread of resistance
52
What drug do we use to look for MRSA?
Cefoxitin Historically, oxicillin has been used but cefoxitin is more stable and better able to induce the mecA gene
53
VISA mechanism
Cell wall thickening traps vancomycin from penetrating to deeper layers of peptidoglycan
54
VRE mechanism
VanA and VanB alter terminal end of D-ala so that vancomycin can no longer bind
55
Species of Enterococcus most likely to be VRE
E. faecium Treat with daptomycin instead
56
Rifampin mechanism
Inhibits bacterial DNA-dependent RNA polymerase -\> inhibits transcription
57
Rifampin resistance mechanism
point mutations in rpoB occur quickly Always must be prescribed in combination
58
Sulfas/trimethoprim mechanism
inhibit folate synthesis, thereby inhibiting purine metabolism (sequential inhibition) leading to troubles in DNA synthesis.
59
Sulfas/trimethoprim spectrum
Broad spectrum against many G+ and G-, also some parasites (i.e. Toxo) and Pneumocystis jiroveci
60
Tetracyclines mechanism
Bind reversibly to 30S subunits, preventing attachment of aminoacyl-tRNA to ribosomal acceptribosomal or in RNA-ribosome complex usually bacterioSTATIC
61
Name two drugs where both MIC and therapeutic drug monitoring are used…
Aminoglycosides Vancomycin - pay attention to MIC because there's a range of effective doses and the higher required doses can cause toxicity problems
62
Vancomycin mechanism
Vancomycin forms hydrogen bonds with D-Ala-D-Ala dipeptide, which inhibits transpeptidase and peptidoglycan crosslinks.
63
Vancomycin spectrum
Gram positive ONLY. Cannot diffuse across LPS outer membrane of G-
64
When reading a KB plate, what are conditions in which the inner "haze" is ignored and the ZOI is measured further out?
1. Proteus will swarm in but it's not actually growing 2. Sulfonamides and trimethoprim disks may have an inner haze due to the organism population going through several doubling generations before inhibition.

M(ASCP) Prep (5 decks)

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