Antibiotics I Flashcards
(104 cards)
1
Q
What do all β-lactam Superfamily of antibiotics target?
A
1) Prevent Crosslinking of peptidoglycan
2) Prevent stable cell wall formation
2
Q
What is the final outcome of β-lactam’s targeting the bacterial cell wall?
A
- “popping”
- Due to osmotic differences between the interior/extracellular environment
3
Q
What are the four major groups of β-lactam’s ?
A
1) Penicillin
2) Cephalosporins
3) Monbactams
4) Carbapenems
4
Q
What causes β-lactam resistance?
A
1) Changes in the Transpeptidase (PBP) receptor
- Gram + bacteria
- Mechanism of resistance in MRSA
2) Production of beta-lactamase enzymes
- Gram - bacteria
3) Decrease permeability of target bacteria
- Modifications of porins
- Efflux pumps (Pseudomonas)
5
Q
What do β-lactam antibiotics inhibit?
A
- Transpeptidase (PBP)
- Thus inhibiting transpeptidation necessary to strengthen cell wall
6
Q
What is the target of β-lactam antibiotics?
A
- Transpeptidase (PBP)
7
Q
T of F
Natural Penicilin has the narrowest spectrum and highly sensitive to Beta Lactamase?
A
- True
8
Q
What is Methicillin used for?
A
- AntiStaphylococcal
- Not used for Tx
- Used to ID MRSA
- Test for Penicillin resistance
9
Q
What are some adverse effects of Penicillin G, V and Methicillin?
A
- Hypersensitivity
- Maculopapular rash
- GI irritation (Secondary infections C. Diff)
10
Q
What is Probenecid used for in pharmacology?
A
- Increases the plasma half life of many antibiotics
- Blocks the Organic Anion Transport (OAT) in the kidneys
- Prevents excretion
11
Q
Why is Pseudomonas resistance to antibiotics?
A
- Due to efflux pumps
12
Q
Only Penicillin that could be given PO with food?
A
- Amoxicillin (Aminopenicillin)
13
Q
Amoxicillin (Aminopenicillin) commonly prescribed for?
A
- ENT and UTI infections
14
Q
What type of infections does Amoxicillin (Aminopenicillin) treat?
A
- All Gram positive
- Some Gram Negative (Where Beta Lactamase not expected)
- Anaerobic infections
15
Q
What does Clavulanic Acid do?
A
- Turns off Beta Lactamase allowing for antibiotic to work
- Extends Gram - Spectrum
16
Q
What are other names for Clavulanic Acid?
A
- β-clavulanic acid
- Clavulanate (Augmentin)
- Beta Lactamase inhibitor
17
Q
What does the combination Tx of
Amoxicillin + Clavulanic acid
fight off?
A
- All Gram positive
- All Gram Negative
- All Anaerobic infections
18
Q
T of F
Amoxicillin + Clavulanic acid will fight off Pseudomonas infections?
A
- False
- Because Pseudomonas has Efflux pumps
19
Q
What medication is an Antipseudomonal penicillin?
A
- Piperacillin + Tazobactam (Zosyn)
20
Q
What does Tazobactam (Zosyn) do to Pseudomonas?
A
- Inhibits Beta Lactamase
21
Q
What penicillin has the broadest spectrum and used empirically with organism is not known?
A
- Piperacillin + Tazobactam (Zosyn)
22
Q
When is - Piperacillin + Tazobactam (Zosyn) usually use?
A
- Empirical treatment of serious or life-threatening infections
23
Q
What coverage does Piperacillin + Tazobactam have?
A
- Widest spectrum
- Gram +
- Gram -
- Pseudomonas
- Anaerobes
24
Q
T of F
Patients with penicillin allergies will be able to take cephalosporins?
A
- True
- 90% no reactions
- 10% might have a reaction administer with caution
25
What do cephalosporins inhibit?
- Cell wall syn
| - Works on Transpeptidase (PBP)
26
What are Cephalosporins commonly used for?
- Very commonly given as presurgical prophylaxis
27
Cephalosporins are classified as?
- Bactericidal
| - Absolute Selectively Toxic
28
Cephalosporins first gen treats?
- Gram +
| - Some Gram -
29
What are Cephalosporins inactive against?
LAME
- Listeria
- Atypicals
- MRSA
- Enterococci
30
T of F
The higher the Cephalosporins generation the wider the spectrum?
- True
31
What are fourth gen Cephalosporins used for?
- Nosocomial infections
- IV only
- Where Beta Lactamase resistance is expected
32
T of F
3rd and 4th Gen Cephalosporins penetrate the CNS?
- True
| - Treats bacterial meningitis
33
Only monobactam that treats Gram - Rods Pseudomonas Aeruginosa ?
- Aztreonam (Azactam)
34
Aztreonam (Azactam) is safe to use in pt's with a penicillin allergy? \
T or F
- True
35
Aztreonam (Azactam) can penetrate the CNS ?
T or F
- True
36
What is Imipenem + Cilastatin (Primaxin) used for?
- Treats serious infections
| - Broadest spectrum among the Beta Lactam's
37
Why is Imipenem given in combination with Cilastatin (Primaxin)?
- Prevents metabolism by renal Dehydropeptidase
| - Stabilizes the drug in circulation
38
T of F
Imipenem + Cilastatin (Primaxin) penetrate the CNS system?
- True
39
Serious side effect of Imipenem (Carbapenems) ?
- Seizures
40
Glycopeptides do not treat Gram - bacteria because?
- Very large
- Too big to cross through porins (transporters) in Gram- bacterial
- Cannot access the peptidoglycan layer of Gram - bacteria
41
Most common resistance of cell wall disruptions in bacteria?
- Overproduction of D-ala – D-ala by the bacterium
| - Acts as a sponge for the drug
42
Least common resistance of cell wall disruptions in bacteria?
- Formation of cell walls using D-ala – D-lactate
- Instead of D-ala – D-ala
- D-lactate cannot be bound by the drug
43
Vancomycin (Vancocin) binds to what on the bacteria?
- Binds directly to D- Ala - D- Ala Peptid
- Forms a cap, blocks cross linking
- Downstream effect, preventing Transpeptidation
- Now cell susceptible to Osmotic pressure = Cell Lysis
44
Last resort drug from life threatening Gram + bacteria?
- Vancomycin
| - Bactericidal
45
What does Vancomycin treat ?
- MRSA Endocarditis
| - Bacteremia
46
Can Vancomycin treat Gram - bacteria?
- No
| - Too big to cross through Gram - Porins
47
T of F
Vancomycin given PO can treat C. Diff ?
- True
- Only reason its given PO
- Usually IV
48
Vancomycin can penetrate the CNS and treat Meningitis?
T of F
- True
| - Even treats MRSA Endocarditis
49
What are the two resistance methods of Vancomycin?
1) D- Ala - D- Lactate mutation (Least Common)
| 2) Over production of D- Ala D- Ala (Most Common)
50
What are the three adverse effects of Vancomycin?
- Nephrotoxicity (Most Common)
- Ototoxcitiy
- Red Man syndrome (Erythematous rash Face, neck, and upper torso) (Most Obvious)
51
What causes Red man syndrome?
Is it a true allergic reaction? No
- Vancomycin
- No, its caused by the release of Histamine from Mast Cells
- Hypotension occurs as well
52
How can you reduce the risk of red man syndrome?
- Slow infusion rate > 60 mins
> 90 mins for high doses
53
How can you counter red man syndrome?
- Antihistamine
54
Where do Protein Syn inhibitors act on?
- Act on the Ribosome sub-units
| - Either 30s or 50s
55
What are the three sites of the ribosome?
A Site = Docking station
P Site = Reading station
E Site = Exit station, cleaved
56
All Protein syn inhibitors are bacteriostatic except for one class, which one?
- Amnioglycosides which is Bactericidal
57
T of F
Protein syn inhibitors are relatively selective? toxic?
- True
58
How do Protein syn inhibitors work?
- Stick to Teichoic and Lipoteichoic acids present in the peptidoglycan cell wall
- Disrupt cell wall syn
59
Where does Tetracycline (Doxycycline) bind to on the bacteria?
- 30s subunit
- A site
- Prevents binding of incoming tRNA on the mRNA template
60
Why are Tetracycline's (Doxycycline) contraindicated in pregnant woman and children < 8?
- Co-deposit with calcium in Bone/Teeth
| - Causes weaknesses, discoloration, and deformities
61
What blocks the absorption of tetracyclines?
- Divalent cations (Mg2+, Ca2+, Fe2+, Al2+)
- Antacids, Tums
- Dairy
62
T of F
Dose adjustments need to be made on pt's with kidney issues if taking Doxcycline?
- True
63
Where does Doxycycline accumulate ?
- Bile
64
What does Doxycycline treat?
- ENT infections
- Bronchitis
- Bladder infections
- Chlamydia
- Gonorrhea
- CA Pneumonia
65
MOA of the microlide Azithromycin ?
- Binds 50S
- Blocks exit tunnel, E Site
- Preventing escape of growing polypeptide chain
66
Azithromycin is consider bacteriostatic and relatively toxic?
T or F
- True
67
How is Azithromycin excreted?
- Cleared entirely through the feces
| - Useful in pt's with renal failure
68
What is the drug of choice to treat Chlamydia?
-Azithromycin (Macrolide)
69
Why does Azithromycin need to be enteric coated?
- Gastric Ph disables the medication
| - Do not give with food either
70
T of F
Azithromycin inhibits CYP450 enzymes?
- False
| - Only Macroglide that does not
71
Because Azithromycin does not modify CYP450 what caution must you take?
- Increases serum levels of other drugs
- Thephylline
- Warfarin
- Cyclosporine
- Methylprednisolone
- Digoxin
72
What is Azithromycin usually prescribed for?
- Chlamydia (DOC)
- Respiratory tract infections
- Travelers Diarrhea
- Skin infections
73
Major adverse effect of Azithromycin?
- Cardiac Arrhythmia's
- QT prolongation
- Torsades de pointes
74
T of F
Azithromycin is safe during pregnancy?
- False
| - Crosses the placenta and breast milk
75
T of F
Almost all MRSA strains are already resistant to macrolides?
- True
| - Because they were next in line after Beta lactams
76
What antibiotic is multimodal interfering with several processes all through the 30S sub-unit?
- Gentamicin (Aminoglycoside)
77
What are the actions of Gentamicin?
1) Blocks complex 30S and 50S association
2) Promotes translation errors
3) Blocks translocation
78
What antibiotic has synergistic effects with cell wall inhibitors?
- Gentamicin + Beta Lactams
| - Enhances uptake of Gentamicin, increasing efficacy
79
What does Gentamicin + Beta Lactams treat?
- Endocarditis and Sepsis
80
What Aminoglycoside displays both
Concentration dependent killing & Significant post antibiotic effects ?
- Gentamicin
81
T of F
You need to adjust Gentamicin doses for pt's with renal disease?
- False
| - Only excreted in the feces
82
What is Gentamicin used to treat?
- Mainly Aerobic Gram -
| - But has coverage for both Gram - & +
83
What are the two toxicities associated with Gentamicin at high doses and extended use?
- Nephrotoxicity
| - Ototoxicity
84
T or F
Gentamicin can be given to pregnant women?
- False
| - It crosses the placenta and into breast milk
85
Lincosamide (Cindamycin) MOA?
- Slow down / Stop bacteria growth
- Binds to the 50s subunit
- Causes peptidyl tRNA dissociation from ribosome
- Blocks the polypeptide exit tunnel
86
T of F
No need to adjust doses for renal and hepatic impairment pt's when treating with Lincosamide (Clindamycin) ?
- True
| - Excreted in the Urine and Feces
87
Whats adverse effect of Lincosamide?
- C. Diff associated Diarrhea
- (Black Box warning)
- Clears out gut flora. Only use for serious infections
88
What does Lincosamide treat?
- Treats MRSA
- MRSA associated soft tissue infections
- Gynecological infections (PID)
89
T or F
You can administer Licosamide and Microglides together?
- False
- They complete with one another for the same binding site
- Cancel each other out
90
Tetracycline bind's where and interfere with what?
- 30s
| - Interferes with binding of tRNA to the ribosomal complex
91
Aminoglycosides bind where and interfere with what?
- 30s
- Causes mRNA to be misread
- Interferes with initiation complex of 30s and 50s with mRNA
92
Linezolid binds where and prevents what?
- 50s P site
| - Prevents formation of the 50/30s complex
93
Macroglides, Clindamycin and Streptogramins binds where and prevents what?
- Block the polypeptide exit tunnel of 50s
| - prevent peptide chain elongation
94
What does Linezolid treat?
- Treats Vancomycin resistant (MRSA) enterococcal infections (VRE)
95
If a drug binds the 50s unit A site and the other drug binds the 50s unit E site there will be no cross resistance?
T of F
- True
- Linezoild 50s P site and Macrolides 50s E site
- No cross resistance
96
What mediation lowers the seizure threshold and has strong serotoninergic effects with SSRI's and Serotonin Rx's?
- Linezolid (Oxazolidinones)
97
Where is Chloramphenicol cleared by ?
- UDP-glucouronidation in the liver (90% Phase II)
| - Adjust doses for pt’s with liver disease
98
What is Chloramphenicol used to treat?
- Last-resort treatment against VRE
Can treat
- Rickettsial infections -Typhus
- Rocky mountain spotted fever
99
T or F
Chloramphenicol is rarely used in the US due to its toxicities?
- True
100
What are important adverse effects of Chloramphenicol ?
- Leukemia’s
- Aplastic Anemias
- Grey baby syndrome
101
Why do infants develop grey baby syndrome with Chloramphenicol ?
- Neonates have not yet developed efficient phase II metabolism
- Drug can build up to unsafe levels
- Inhibits electron transport chain
- Reduces energy production
- Ashen skin color
- Hypotension
- Hypothermia
- Used in caution with infants LOW DOSES
102
What are the three mechanisms for protein sys inhibitors resistance?
1) Decreased accumulation (Reduced permeability of Increased Efflux pumps)
2) Chemical modifications that inactive the drug
3) Changes in biding site on Ribosome (Antibiotic protection proteins, Ribosomal subunit mutations)
103
What is the most common mechanism for protein syn inhibitor resistance?
- Changes in biding sites on ribosome
| - Ex rpsL mutation on 50s prevents binding of Aminoglycoside Streptomycin
104
masAB ToIC exporter pumps out Macroglides in many Gram - bacteria, what resistance mechanism is this an example of?
- Decreased accumulation
