Antibiotics Flashcards
(131 cards)
1
Q
Definition of antibiotic
A
substance or compound that kills or inhibits growth of bacteria
2
Q
Endogenous antibiotic
A
lysozyme from mucus and tears
3
Q
selective toxicity
A
ability of antibiotic to cause harm to bacteria without causing damage to the host
4
Q
Antibiotic potential targets
A
cell wall synthesis, membrane integrity, folate synthesis, DNA/RNA synthesis, protein synthesis
5
Q
Bactericidal
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kills bacteria, does not rely on immune system for clearance
6
Q
Bacteriostatic
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bacteria “lassoed,” not propagating or proliferating, immune system able to overwhelm bacteria
7
Q
Spectrum
A
broad: targets a variety of species
Narrow: targets a very specific species
8
Q
Antibiotic resistance
A
bacteria resist actions of frequently used drugs, can mutate
9
Q
Major cause of abx resistance
A
over prescription and misuse
10
Q
Prevention of abx resistance
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appropriate abx, use as indicated(!)
11
Q
Synergy
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inhibitory or killing effects of two or more abx in combination are greater than their effects individually
12
Q
Antagonism
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inhibitory or killing effects of two or more abx in combo are less than their effects individually
13
Q
Cell wall synthesis inhibitors
A
Beta lactams (penicillins, cephalosporins, carbapenems), monobactams, glycopeptides and lipoglycopeptides
14
Q
How do glycopeptides and lipogylcopeptides differ from beta lactams?
A
glyco/lipoglyco peptodes: inhibit cell wall synthesis by binding to D-alanyl-Dalanine terminus
Beta lactams: interact with transpeptidase
15
Q
Which antibiotic relies on renal dipeptidase inhibitor celastatin?
A
carbapenems, imipenem
16
Q
What differentiates second gen cephalosporins from cephamycins?
A
cover both G+ and G- while cephamycins are active against B. fragilus and some Serratius spp.
17
Q
What is the general sprectrum of coverage for monobactam aztreonam?
A
mostly G-, aerobic bacteria
18
Q
How does resistance to methicillin happen in MRSA?
A
transpeptidase (penicillin binding protein) mutation prevents methicillin binding
19
Q
Protein Synthesis Inhibitors
A
50s: oxazolidinones, macrolides, ketolides, streptogramins
30s: tetracyclines, aminoglycosides, glycylcyclines
20
Q
What is the difference in MOA between oxazolidinones and streptogramins?
A
streptogramins: prevent translation by binding to 50s
oxazolidinones: prevent initiation
21
Q
DNA/RNA synthesis inhibitors
A
Fluoroquinolones
22
Q
What proteins do fluoroquinolones inhibit?
A
Topoisomerase II in G+ bacteria, Topoisomerase IV in G- bacteria
23
Q
Membrane integrity and folate synthesis inhibitors
A
membrane integrity: polymyxins
Folate synthesis: sulfonamides and benzylbiyrimidines
24
Q
Why are sulfonamide and benzylpyrimidines synergistic?
A
both inhibit folate, sulfonamide inhibits PABA, benzylpyrimidines inhibit dihydrofolate reductase
25
Are polymyxins active against G+ bacteria?
no, target LPS on G- bacteria
26
Penicillin MOA
interfere with transpeptidation reaction, inhibiting cell wall synthesis by preventing cross linking of components
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Method of penicillin resistance
Beta lactamases break down beta lactam ring; porin and PBP structure alteration; increased efflux
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Method of Penicillin G resistance
beta lactamases
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Spectrum of Penicillin G activity
G+ coccii (strep spp.), G- coccii (N. meningitidis), T. pallidum, non-B-lactamase anaerobes (C. perfringens)
30
Penicillin G AE
hypersensitivity reactions (anaphylaxis), N/V/D
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Aminopenicillins MOA
cell wall synthesis inhibitors
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Aminopenicillins mechanism of resistance
Beta-lactamases
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Spectrum of aminopenicillins
G-, G+; E. coli and other enterics; H. influenzae, Klebsiella spp., Proteus spp., B. fragilis
34
Penicillinase resistant penicillins drugs
methicillin, nafcillin, oxacillin,dicloxacillin
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Resistance to penicillinase resistant penicillins
reduced affinity for med in binding pocket of transpeptidase
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Spectrum of penicillinase resistant penicillins
staphylococcal spp.
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Antipseudomonal penicillins drugs
carboxypenicillins, ureidopenicillins
38
Mechanism of resistance for antipseudomonal penicillins
beta-lactamase (although should be co-formulated with tazobactam to inhibit beta-lactamase)
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Spectrum of antipseudomonal penicillins
P. aeruginosa, G- bacilli, E. coli, H. influenzae, and B fragilis
40
Cephalosporin MOA
inhibits transpeptidation reaction by binding and inhibiting transpeptidase
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Cephalosporin mechanism of resistance
beta-lactamases, altering porins and molecular structure of transpeptidase, efflux pumps
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Cephalosporin AE
maculopapular rash, eosionophilia, fever
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First generation cephalosporin drugs
cefadroxin, cephalothin, cephradine, cefazolin, cephalexin
44
Spectrum of first gen cephalosporins
G+ cocci (S. aureus); NOT MRSA, B. fragilis, enterococci, or S. epidermidis; G- bacteria such as M. catarrhalis, K. pneumonie, E. coli, Proteus mirabilis
45
Second generation cephalosporin drugs
cefuroxime, loracarbef, cefonicid, cefamanadole, cefalcor, cefoxitin
46
Spectrum of second gen cephalosporins
H. influenzae, N. meningitidis, S. pneumonia, cefoxitin and cefotetan are active against B. fragilis and some Serratia spp.; NO enterobacter spp.
47
Third generation cephalosporin drugs
cefotaxime, cefixime, cefdinir, ceftibuten, ceftazimide, ceftriaxone
48
Spectrum of third gen cephalosporins
expansion of G- coverage, slightly less active against G+ like Strep and Staph spp.; work well against Neisseria and Haemophilus spp. (Not Acinetobacter, Serratia, Enterobacter spp.)
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Only third gen cephalosporin active against P. aeruginosa
ceftazidime
50
Cefdinir is active against....
E. coli, S. pyogenes, H. influenzae, P. mirabilis
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Ceftriaxone AE
biliary pseudolithiasis, jaundice
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Fourth gen cephalosporin drugs
cefepime
53
Spectrum of cefepime
P. aeruginosa, Enterobacter spp.; Poor activity against B. fragilis
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Fifth gen cephalosporin drugs
ceftaroline fosamil, ceftolozane
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Spectrum of fifth gen cephalosporins
MRSA, Pseudomonas spp.; Pseudomonas spp.
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Carbapenem drugs
ertapenem, meropenem, imipenem
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Carbapenems MOA
bind to and inhibit transpeptidase, inhibiting cell wall synthesis
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Carbapenem resistance
shrinking of porin channels, upregulation of degradation enzymes
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Carbapenem spectrum
gram-negative and positive bacteria
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Imipenem spectrum
G+ anaerobes, and most G- rods; P. aeruginosa, Listeria, staphylococci, enterococci, streptococci, Acinetobacter, B. fragilis
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Bugs resistant to Imipenem
B. cepacia, C. diff. MRSA, E. faecium
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Ertapenem spectrum does not include...
P. aeruginosa, Acinetobacter spp. and enterococcus
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AE with imipenem
skin rashes, diarrhea, vomiting, nausea; if the pt is in renal failure imipenem may cause seizures
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Monobactam available in the US
Aztreonam
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Aztreonam MOA
inhibits G- transpeptidase, preventing cell wall synthesis
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Aztreonam spectrum
G- aerobic bacteria, enterobacteriaceae, P. aeruginosa, H. influenzae
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Aztreonam AE
pts allergic to ceftazidime will also have a sensitivity; elevations of serum aminotransferases, skin rashes
68
Glycopeptide drug
vancomycin
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Glycopeptide MOA
bind to D-alanyl-Dalanine terminus of cell wall precursor which prevents linking of peptidoglycans
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Lipoglycopeptide MOA
dimerize and imbed their structure into the bacterial cell membrane, increasing potency of glycopeptide
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Glycopeptide resistance
E. faecium; change in glycopeptide vinding site
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Glycopeptide spectrum
G+ bacteria (including drug resistant strep and enterococci, MRSA)
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Bacteria resistant to glycopeptides
G- bacilli and mycobacterium, Lactobacillus
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Glycopeptide administration
must be thru IV, cannot be absorbed across GI mucosa
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Glycopeptide AE
infusion reactions, nephrotoxicity, hypotension, tachycardia and flushing (Red man syndrome)
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Beta lactamase inhibitors drugs
not antibiotics; clavulanic acid, sulbactam, tazobactam
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Beta lactamase MOA
inhibit beta lactamase
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Spectrum of Beta lactamase coverage
dependent on paired antibiotic such as aminopenicillins and piperacillin
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Oxazolidinone drugs
linezolid
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Oxazolidinone MOA
protein synthesis inhibitor, bind to P site on 50S ribosome
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Oxazolidinone restriction
point mutation on 23S rRNA
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Oxazolidinone spectrum
G+ bacteria, poor coverage of G-
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Oxazolidinone AE
myelosuppression, mitochondrial toxicity, drug-drug interactions
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Myelosuppression in oxazolidinone AE
thrombocytopenia
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Mitochondrial toxicity in oxazolidinone AE
lactic acidosis, optic neuritis, peripheral neuropathy
86
Drug-drug interactions in oxazolidinone AE
SSRIs, MAOs--can lead to serotonin syndrome (HA, palpitation, hypertensive crisis)
87
Macrolides that are clinically used
erythromycin, clarithromycin, azithromycin, fidaxomicin
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Macrolides MOA
prevents tRNA translocation from A site to P site, inhibits 50S, and conformational protein change
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Macrolide resistance
drug efflux, methylase enzyme production protects ribosome, macrolide degradation, 50S mutations
90
Erythromycin spectrum
all gram positive bacilli, some gram negatives (Bartonella, T. pallidum, Neisseria); inactive against most aerobic enteric G- bacilli
91
Azithromycin spectrum
M. catarrhalis, Chalmydia spp., B. burgdorferi, H. pylori, H. influenzae
92
Clarithromycin spectrum
streptococci, staphylococci, H. influenzae
93
Fidaxomicin spectrum
C. difficile
94
Macrolide AE
N/V/D, anorexia, epigastric distress, arrhythmias, hepatotoxicity; skin eruptions, eosinophilia, and fever
95
Streptogramin drugs
streptogramin A and B
96
Streptogramin MOA
inhibit protein synthesis by binding 50S, inhibits elongation and induces early termination
97
Streptogramin resistance
enzymatic inactivation, altered binding sites, drug efflux
98
Streptogramin spectrum
gram positive cocci, M. pneumoniae, C. pneumoniae, Legionella spp.; NOT G- bacteria, not E. faecium
99
Streptogramin AE
pain and arthalgia-myalgia syndrome
100
Tetracycline drugs
minocycline, demeclocycline, doxycycline
101
Glycylcycline drug
tigecycline
102
Tetra/glycylcycline MOA
bind 30S ribosome and prevent tRNA from entering A site, inhibiting protein synthesis
103
Tetra/glycylcycline resistance
decrease influx or increase efflux, upregulation of a protein that dislodges tetracyclines, enzymatic inactivation
104
Tetracycline spectrum
more active against G+; anaerobes, chlamydiae, mycoplasmas and rickettsiae; MRSA, B. anthracis, L, monocytogenes, V. cholera, Legionella, Plasmodium, T. pallidum
105
Glycylcycline spectrum
same activity as tetracyclines but greater activity against enterococci, enterobacteriaceae, Acinetobacter spp., B. fragilis
106
Tetra/Glycylcycline AE
GI irritation, pts at increased risk for C. diff, bind well to developing bones and teeth (will develop a permanent brown stain)
107
Aminoglycoside drugs
streptomycin, gentamicin, neonmycin, kanamycin
108
Aminoglycoside MOA
bind to 30S subunit and act as an irreversible inhibitor (inhibit initiation, continuation of translation, introduction of errors in developing protein)
109
Aminoglycoside resistance
enzymatic inactivation, decreased influx, mutations in 30S subunit prevent binding
110
Aminoglycoside spectrum
aerobic G- bacteria; Enterobacter spp., E. coli, K. pneumoniae, P. aeruginosa, Serratia spp.
111
Aminoglycoside AE
nephrotoxic (Gentamicin, neomicin), ototoxic (Gentamicin and streptomycin cause vestibular damage)
112
Fluoroquinolones drugs
norfloxacin, ciprofloxacin, ofloxacin, gatifloxacin
113
Fluoroquinolone MOA
inhibit transcription and replication of DNA by binding topoisomerase II
114
Fluoroquinolone resistance
mutations in binding region on DNA gyrase, active efflux, or upregulation of proteins that shield DNA gyrase
115
Fluoroquinolone spectrum
active against G+ and G-; Campylobacter spp., Enterobacter spp., Shigella, Proteus, E. coli, Legionella, Chlamydia
116
Levofloxacin is a good drug for what bacteria
S. pneumon iae
117
Ciprofloxacin is a good drug for what bacteria
P. aeruginosa
118
Fluoroquinolone AE
GI side effects, increased C. diff risk, tendon rupture, QT prolongation
119
Sulfonamide drug
sulfamethoxazole
120
Benzylpyrimidine drug
trimethoprim
121
Trimethoprim MOA
inhibits dihydrofolate reductase (cannot make purines)
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Sulfamethoxazole MOA
inhibit dihydropteroate synthase, cannot produce folate
123
Sulfamethoxazole resistance
bacterial overproduction of PABA, reduced binding to enzyme, decrease influx
124
Trimethoprim resistance
reduced bacterial permeability, upregulation of dihydrofolate reductase, reduced binding affinity to enzyme
125
Timethoprim monotherapy
can be used to treat UTIs, but combination therapy is more likely
126
TMP/SMX spectrum
S. epidermidis, S. aureus, S. pyogenes, Viridians, Serratia, shigella, salmonella, enterobacter, P. mirabilis, Nocardia, P. jiroveci, Haemophilus, M. catarrhalis
127
TMP/SMX AE
anemia, leukopenia, granulocytopenia, N/V, photosensitivity, fever, urticaria, Stevens-Johnson syndrome
128
Polymyxin MOA
Disrupt G- membrane, bind to and inactivate endotoxin
129
Polymyxin resistance
rare, only an issue in some Klebsiella and Acinetobacter spp.
130
Polymyxin spectrum
G- bacteria, aerobes; NOT proteus or serratia, neisseria, burkholderia spp.
131
Polymyxin AE
nephrotoxicity, slurred speech, vertigo, paresthesia, apnea, muscle weakness
