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Lecture 5 Flashcards

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1
Q

What are three forms of Abx synergism?

A
  1. Block sequential steps
  2. Facilitate drug entry (this is done by cell wall or membrane inhibitors)
  3. Inhibit a drug detox enzyme
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2
Q

What is an example of syergism?

A

Loperamide and Tet allow entry of each other

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3
Q

Example of Abx antagonism?

A

Chloramphenicol and PCN If chloramphenicol acts first, it is bacteriostatic and PCN can’t kill

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4
Q

What is SxT

A

Sulmethoxazole/Trimethoprim (Septra and Bactrim)

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5
Q

What structural congregation of bacteria are very difficult to kill?

A

Biofilms

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6
Q

When should you use multiple Abx?

A

System infection To delay resistance in long-term use For synergism

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7
Q

What is Synercid?

A

Quinupristin and dalfopristin Together are bacteriocidal

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8
Q

What is the best treatment for biofilms?

A

Prevention

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9
Q

How are new coatings on implantable devices working to inhibit biofilms?

A

Kill with cationic detergent and then hydrolyze

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10
Q

Beta lactam mode of action

A

Cell wall inhibitors by:
Inhibiting transpeptidation
Activate autolysins

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11
Q

Causes of beta lactam resistance?

A

Beta lactamases
Lack of PBPs (PCN binding proteins)
Autolysin mutations

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12
Q

Common beta-lactamase inhibitors?

A

Clavulinic acid
Sulbactam
Tazobactam

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13
Q

What are the natural forms of PCN?

A

Pen G

Pen V

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14
Q

Use for natural PCNs?

A

GramPos

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15
Q

What forms of PCN are beta-lactamase resistant? What is their weakness?

A

Nafcillin
Oxacillin
Cloxacillin
They have lower activity

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16
Q

What is spectrum of expanded spectrum PCNs?

A

GramPos

GramNeg

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17
Q

What are the expanded spectrum PCNs?

A

Ampicillin
Piperacillin
Mezlocillin
Ticarcillin (vs. pseudomonas)

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18
Q

What are the acid resistant PCNs?

A

Amoxycillin
Pen V
Oxacillin

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19
Q

What is ampicillin often paired with?

A

Sulbactam

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20
Q

What is zosyn, tazomed?

A

Piperacillin + tazobactam

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21
Q

What is a benefit of cephalosporins?

A

Less sensitive to beta-lactamases

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22
Q

What are the classes of beta-lactams?

A

PCNs
Cephalosporins
Carbapenems
Monobactams

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23
Q

1st gen cephalosporin spectrum?

A

GramPos

For prophylatic use only

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24
Q

1st gen cephalosporins?

A

Cephalexin
Cephalothin
Cefazolin

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25
2nd gen cephalosporin spectrum
GramPos and GramNeg Will cover bacteroides Does not cover pseudomonas
26
2nd gen cephalosporins
Cefaclor Cefuroxime Cefoxitin
27
3rd gen cephalosporin spectrum
GramPos, GramNeg, and pseudomonas | Used for GramNeg only to protect against overuse
28
3rd gen cephalosporins
Ceftazidime Cephotaxime Cephtriaxone
29
4th gen cephalosporin spectrum
Slight expanded from 3rd gen
30
Monobactam spectrum
GramNeg only! | No GramPos or anaerobes
31
4th gen cephalosporin
Cefepime
32
5th gen cephalosporins spectrum
Activity against MRSA and drug resistant S. pneumoniae
33
5th gen cephalosporins
Ceftaroline
34
Benefit of monobactams
Resistant to beta-lactamases
35
Monobactam example
Aztreonam
36
Carbapenem spectrum
Broad | GramPos and GramNeg
37
Risk of carbapenems
May be toxic --> seizures
38
Carbapenem examples
Imipenem, ertapenem, meropenem
39
Meropenem benefit
Might be less toxic than other carbopenems
40
What is a side effect of cephalosporins
Might cause thrombophlebitis
41
Who might experience a PCN rash?
Someone infected with mono virus
42
Bacitracin mode of action
Blocks de~P of bactoprenol
43
Bacitracin spectrum
Topical only because renal toxicitiy, poorly absorbed | GramPos (commonly used with others)
44
Glycopeptide Abx examples?
Vancomycin | Telavancin
45
Glycopeptide Abx mode of action?
Bind to amino acid side chain | Block transglycosylation and transpeptidation
46
What causes glycopeptide Abx resistance?
Organism uses ala-pyruvate instead of ala-ala on pentapeptide side chain
47
What two genetic alterations leads to glycopeptide Abx resistance?
VanA gene confers full glycopeptide resistance | VanB gene confers moderate glycopeptide resistance
48
Glycopeptide Abx uses?
Staphylococci Enterococci NOT GramNeg
49
Cycloserine action?
Inhibits alanine racemase
50
Cycloserine side effect?
Neurotoxic
51
Uses for cycloserine?
UTIs | 2nd line drug for TB
52
What drug classes are cell wall inhibitors?
Beta-lactams Bacitracin Glycopeptides Cycloserines
53
What special drugs are used for mycobacterium?
``` Isoniazide Ethionamide Ethambutol Pyrazinamide Rifampicin ```
54
Isoniazide and ethionamide for mycobacterium action
Inhibit mycolic acid synthesis (pyroxidine step)
55
Ethambutol mechanism in mycobacterium
Inhibits arabinogalactan synthesis (rapid resistance)
56
Pyrazinamide mechanism in mycobacterium
Inhibits trans-translation
57
What are the 5 most broad classes of antibiotics?
``` Cell wall inhibitors Cell membrane disrupter Antimetabolites Nucleic acid inhibitor Protein synthesis inhibitors ```
58
What are the two classes of cell membrane disrupters?
Polymixin | Daptomycin
59
What pathway do sulfonamides and trimethoprim interrupt?
Pyrimidine synthesis by blocking PABA --> pyrimidine synthesis
60
Polymyxin mode of action?
Dissolve phosphatidylethanolamine | Specialized PL in GramNeg membranes
61
Polymyxin side effects
Toxic so often used with other antibiotics or as a last resort
62
Daptomycin mode of action
It's a cyclic lipopeptide that dissolves in a membrane and disrupts the membrane potential
63
Daptomycin uses?
GramPos Cocci including MRSA | Must be given IV beta-lactams
64
What are the main antimetabolite Abx
Sulfonamides | Trimethoprim
65
What would cause resistance to sulfonamides or trimethoprim?
Overproduction of PABA
66
What are uses for trimethoprim and sulfonamides?
Nocardia | Synergistic for UTI, Salmonella, Shigella
67
What are the main nucleic acid inhibitors?
Fluoroquinolones Fidaxomycin Rifamycin Metronidazole
68
What are the fluorquinolones?
Ciprofloxacin | Moxifloxacin
69
Fluoroquinolone MOA
Inhibit DNA gyrase
70
Fluoroquinolone resistance?
Altered DNA gyrase, drug exclusion
71
Fluoroquinolone use?
UTI's | GramNeg and GramPos infections including mycobacteria and pseudomonas
72
Fidaxomycin aka?
Dificid
73
Fidaxomycin MOA
Targets "switch region" of RNAP | Inhibits RNAP-DNA interaction
74
Fidaxomycin uses
Vanco alternate for c-diff
75
Rifamycin aka
Rifampin Rifabutin Rifaximin
76
Rifamycin MOA
Blocks RNAP elongation subunit
77
Rifamycin resistance
Altered RNAP polymerase beta subunit
78
Rifamycin uses
with Isoniazid to delay resistance in mycobacteria Crosses CNS so useful for meningitis Blocks assembly of poxvirus
79
Rifamycin side effects?
Turns skin and urine orange (harmless)
80
Metronidazole MOA
Is partially reduced | Interacts with DNA to break strand
81
Where can metronidazole be used?
Only anaerobic conditions | If aerobic, it will become oxidized and ineffective
82
Metronidazole uses?
``` Antiprotozoal (Giardia) Anaerobic bacteria (Bacteroides, clostridium) ```
83
Main protein synthesis inhibitors
``` Aminoglycosides Tetracycline Chloramphenicol Macrolides Lincosamides Others ```
84
Aminoglycoside AKA
``` Streptomycin Neomycin Gentamycin Tobramycin Amikacin ```
85
Aminoglycosides MOA
Binds to 30S ribosome | Blocks first Met being added
86
Aminoglycoside resistance
Altere P12 ribosomal protein Aminoglycosidase Altered permeability (Streptococci)
87
Aminoglycoside uses
GramNeg enterics | Use with cephalosporins or PCNs (facilitate entry)
88
Tetracycline AKA
Doxycycline | Tigecycline
89
Tetracycline MOA
Inhibits binding of aa-tRNA to the A-site of 30S
90
Tetracycline resistance
Efflux pumps
91
Tetracycline uses
Rickettsia Chlamydia Mycoplasms
92
Tetracycline side effects
``` Toxicity Dizziness Tinnitus Fluorescent teeth Possible bone damage in newborns Replacement of native flora ```
93
Chloramphenicol MOA
Inhibits peptidyl transferase reaction 50S
94
Chloramphenicol resistance
Chloramphenicol acetyl transferase | No longer the drug of choice
95
Macrolides AKA
Erthromycin Clarithromycin Azithromycin
96
Macrolide MOA
Binds to rRNA and inhibits translocation
97
Macrolide resistance
Methylation of rRNA
98
Macrolide uses
GramPos | Some GramNeg
99
Lincosamides AKA
Clindamycin
100
Lincosamides MOA
Same as macrolides | Binds to rRNA and inhibits translocation
101
Lincosamide uses
Anaerobes (bacteroides) Anti-malarial Associated with c-diff development
102
Nitrofurantoin MOA
Inhibits 30S
103
Nitrofurantoin uses
UTI because it concentrates in urine
104
Mupirosin MOA
Inhibits ile-tRNA synthase
105
Mupirosin uses
Topically for GramPos
106
Streptogramins "Synercid" combination
Quinupristin + dalfopristin
107
Streptogramin MOA
Inhibits 50s
108
Streptogramin uses
VRE and VRSA
109
Oxazolidinones AKA
Linezolid
110
Oxazolidinone MOA
Inhibits 50s
111
Oxazolidinone uses
VRE and MRSA
112
Methenamine MOA
Releases formaldehyde to acidify urine
113
Methenamine uses
UTI
114
What two drugs are being tested to wake up persister cells
C10 | BF8

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